Acute muscle swelling effects of a knee rehabilitation exercise performed with and without blood flow restriction

Christopher J. Cleary; Trent J. Herda; Austin M. Quick; Ashley A. Herda

doi:10.1371/journal.pone.0278540

Abstract

This study assessed the acute effect of adding blood flow restriction (BFR) to quad sets on muscle-cross sectional area (mCSA), muscle thickness (MT), echo intensity (EI), and subcutaneous fat-normalized EI (EI_NORM) of the superficial quadriceps muscles. Twelve males and 12 females (mean±SD; age (yrs): 21.4±2.9; stature (m): 1.76±0.1; body mass (kg): 77.7±2.9) performed 70 repetitions (one set of 30, three sets of 15 repetitions) of bodyweight quad sets separately on each leg, with or without BFR (CON) applied. Rating of perceived exertion was recorded following each set. Panoramic ultrasound images of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) were captured prior to (PRE), immediately after (IMM-POST), 30- (30-POST), and 60-minutes after (60-POST) after exercise. Sex x condition x time repeated measures ANOVAs assessed differences at p<0.05 for each muscle and dependent variable separately. Although males had larger VM and VL mCSA and VL MT (p<0.05), there were no acute changes from PRE to IMM-POST (p>0.05). There was a 3-way interaction in VL mCSA (p = 0.025) which indicated BFR was greater than CON at IMM-POST by 7.6% (p = 0.019) for males only. Females had greater EI in the VM and VL than males (p<0.05), yet males had greater EI_NORM for each muscle (p>0.05) and EI_NORM did not change over time or treatment (p>0.05). The lack of changes in MT, EI, and EI_NORM indicate that unloaded quad sets do not provide a stimulus to promote fluid shifts or acute changes in muscle size with the exception of IMM-POST in the VL for males. Future research should attempt to elucidate the acute muscular responses of BFR application for lightly loaded rehabilitation exercises in the clinical populations for which they are prescribed.

Citation: Cleary CJ, Herda TJ, Quick AM, Herda AA (2022) Acute muscle swelling effects of a knee rehabilitation exercise performed with and without blood flow restriction. PLoS ONE 17(12): e0278540. https://doi.org/10.1371/journal.pone.0278540

Editor: Emiliano Cè, Universita degli Studi di Milano, ITALY

Received: May 26, 2022; Accepted: November 17, 2022; Published: December 22, 2022

Copyright: © 2022 Cleary et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the article and its Supporting Information files.

Funding: The author(s) received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Blood flow restricted (BFR) resistance training has become a widely used exercise training modality. BFR has become popular in general training for hypertrophy, training older adults, and in clinical practice following injury [1]. BFR resistance training is performed with significantly lower external loads than traditional high-load training and has been thoroughly applied in clinical and aging populations [2–4]. Although the exact physiological mechanisms of BFR resistance training remain unknown, it could be due to multiple systemic and/or local factors. These include, but are not limited to, swelling [5–7], metabolic stress [4], endocrine responses [8], and/or satellite cell recruitment [9].

Multiple studies have assessed the acute effect of BFR resistance exercise using low-load concentric movements on lower-limb muscle cross-sectional area (mCSA), muscle thickness (MT) [10–12] and echo intensity (EI), which has been suggested to represent changes in intracellular fluid [13]. The changes in intracellular fluid may be due to an increase in blood flow to the working musculature, cellular swelling, and/or metabolic buildup during and following activity [14]. These studies have presented mixed results, with Hackney et al. [11] showing no significant differences compared to baseline in rectus femoris mCSA immediately after and 5-minutes after BFR knee extensions when compared to low-load non-BFR exercises. Conversely, the MT of the vastus lateralis can be elevated immediately after BFR knee extensions with a concomitant decrease in EI [10] and MT can be elevated up to 3-hours after BFR knee extensions compared to baseline [12], purportedly due to local swelling. Additionally, the perceived effort of BFR-mediated “work” has been reported to be much higher than non-BFR movements, hence why a standard protocol for BFR includes only 20–30% 1-repetition maximum load during dynamic, concentric resistance exercises [11, 15].

Despite the ever-increasing amount of BFR research, there is a lack of literature on the addition of BFR to bodyweight only rehabilitation exercises. For example, following knee surgery, straight-leg raises, heel slides, and isometric quadriceps contractions “quad sets” are commonly prescribed [16–18], but without BFR. Typically, these are utilized in the early stages of rehabilitation (1–14 days post-surgery), with or without electrical stimulation or other therapeutic modalities [16]. If exercise modalities that maintain muscle mass after surgery can be utilized earlier in the recovery process, then perhaps the long-term deficits between a surgical limb and a non-surgical limb can be attenuated [19, 20]. If BFR-mediated resistance exercise can stimulate muscular changes in healthy adults [10, 12], studies should then assess the acute responses (e.g., changes in muscle size) of knee rehabilitation exercises performed with BFR, to determine if this provides a unique response. A substantial amount of the existing BFR literature has included both male and female participants, yet do not elucidate any sex-specific differences in BFR-driven muscular responses [19, 21, 22] and suggest future research should investigative if there are unique sex-related responses to BFR. To date, two investigations have compared sex and reported varying outcomes. Young et al. demonstrated similar trends between sex in vastus lateralis MT changes after BFR knee extensions [12] and Bell et al. also noted no differences in MT between sex after BFR resistance exercise [10].

Based on the potential efficacy of the addition of BFR to a knee rehabilitation exercise, the primary aim of this study was to assess acute changes in mCSA, MT, EI, and perceived exertion in males and females following quad sets with or without BFR. A secondary purpose was to assess any differences in these responses by sex. It was hypothesized that quad sets with BFR will require greater effort and elicit a muscle swelling response, as measured via mCSA, EI, and MT. It was also hypothesized that no differences would exist between males and females’ responses to the BFR or CON treatment applied.

Materials and methods

A within-subjects repeated measures design was completed where participants performed unilateral quad sets separately on both legs with one leg exercising with BFR and the contralateral leg exercising without BFR (CON), under random assignment to the dominant and non-dominant legs. Condition order was randomized per participant with 10-minute rest between conditions. Panoramic ultrasound scans of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) were captured prior to (PRE), immediately after (IMM-POST), 30-minutes (30-POST), and 60-minutes (60-POST) following the respective exercise protocols (S1 Fig 1 in S1 File). Rating of perceived exertion (RPE) was measured after each exercise set on a CR-10 scale [23]. Both conditions required participants to perform a total of 70 repetitions per leg. All participants provided written informed consent and completed a health and exercise history questionnaire prior to participation. All protocols were approved by the University IRB (#00147840) in accordance with the Declaration of Helsinki.

Procedures

Participants.

Twenty-four participants [12 males (age: 21.4±2.7 years; stature: 1.81±0.5 meters; body mass: 85.3±6.4 kg; and BMI: 26.1±2.1 kg∙m²) and 12 females (age: 21.3±3.1 years; stature: 1.70±0.7 meters; body mass: 70.2±8.6 kg; and BMI: 24.3±3.4 kg∙m²)] volunteered to participate in the present study from the university and local community. This sample size was determined from an a priori power analysis conducted in G*Power (G*Power 3.1, Kiel, Germany) using a moderate effect size of f = 0.25 and type I error rate of 0.05. A total of 24 participants was required to achieve statistical power of 0.80. The participants met the following inclusion criteria: male or female between 18–30 years, a body mass index between 18–30 kg∙m^-2, and resistance training experience of at least 2x/week for the past 6 months, which indicated they were not sedentary, had experience with exercise, and is in agreement with previous samples [11, 12]. Participants were excluded if they had a history of cardiovascular, metabolic, or nervous system disorders, had any current orthopedic or musculoskeletal injuries, or recently (≤ 6-months) underwent lower-body surgery.

Ultrasound image acquisition.

After the participant’s height and weight were taken and recorded, they laid supine on the examination table quietly for ~5 minutes [24] while the principal investigator explained the exercise techniques, prepared for the ultrasound measurements, and demonstrated the exercise technique. Ultrasound images of the VM, VL, and RF were captured at PRE, IMM-POST, 30-POST, and 60-POST of each condition (Fig 1). Participants remained supine on the examination table throughout the duration of the study visit, including between image acquisition timepoints. At PRE, the ultrasound measurements were taken consecutively, beginning with the leg that was randomized to exercise first. Panoramic images were captured in the transverse plane for the VL at 50% of the distance between the greater trochanter and the lateral epicondyle of the femur and for the RF at 50% of the distance from the superior border of the patella and the greater trochanter [25]. The VM was imaged on the medial aspect of the thigh, 10 cm above the superior pole of the patella [26]. A trained investigator captured all images using a Logiq e R7 diagnostic ultrasound (GE Healthcare, Wauwatosa, WI, USA) set in LOGIQ View^(R) to capture panoramic images with a linear array transducer (Model L4-12t-RS, 4.2–13.0 MHz; 12.7 x 47.1 mm probe surface area). Participants laid supine on a padded examination table with a 6” diameter PVC pipe placed under the popliteal fossa to elevate the thighs during ultrasound measurements. Scan depth was set to 6 cm for all participants, while gain and transducer frequency were 68 dB and 10 MHz, respectively, and these settings remained constant for each image acquisition. Water-soluble gel was applied to the skin and transducer to enhance image quality during all ultrasound measurements.

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Fig 1.

Image analysis parameters for the VM (a), VL (b), and RF (c). The arrows represent MT, straight lines represent subcutaneous fat thickness, and the dotted line represents mCSA. The histogram displays the uncorrected EI (mean) of each image.

https://doi.org/10.1371/journal.pone.0278540.g001

Exercise protocols.

Exercise condition order and leg allocation was randomized using Microsoft Excel’s (Microsoft Office, Microsoft, Redmond, WA, USA) randomization function (S1 Fig 1 in S1 File). After the PRE ultrasound scans, participants were provided demonstrations on proper quad sets technique: the exercising leg was extended while the non-exercising leg was bent at approximately 90° with the foot flat on the patient table and the participant’s hands placed on the table to support the trunk in an upright position (S1 Fig 2 in S1 File). Participants were cued to “squeeze the muscles in the front of your thigh, which may cause your knee to press down to the table” during all repetitions [17, 27]. One set of 30 repetitions followed by three sets of 15 repetitions with 30 seconds of rest between sets were performed separately on each leg [3, 19]. Ten minutes after the completion of the first exercise protocol on the first leg, the second exercise protocol (BFR or CON) was repeated on the opposite leg using the same procedures.

During the BFR condition, a 10-cm wide cuff (Smart Cuffs, Smart Tools Plus, Strongsville, OH, USA) was applied to the proximal portion of the participant’s thigh, near the inguinal crease, and inflated to 80% of the participants arterial occlusion pressure as determined by an internal doppler sensor. The cuff remained inflated between sets and was removed upon conclusion of the final set. Total occlusion time including inflation was recorded. The CON condition was performed on the contralateral limb without BFR applied. After each set, RPE on a CR-10 scale was measured [23]. Based on the randomized nature of limb and condition set-up, twelve participants completed the CON condition first with the other 12 completing the BFR condition first and ten participants exercised with the left leg first. Three participants reported the left leg as their dominant leg through being asked which leg they would prefer to kick a ball with [28].

Ultrasound image analysis

All images were saved on the ultrasound hard drive and subsequently exported to an external USB drive for analyses in ImageJ (NIH, Bethesda, MD, USA). Prior to image analyses, each image was blinded by an external investigator, so that the image analyst would not be influenced by the timepoints or conditions [12]. Similar to previous research [29], MT (cm) was defined as the distance between the superior and inferior borders of the muscle at measured at 50% of the horizontal distance of the muscle belly, mCSA (cm²) was determined by manually tracing the entirety of the muscle’s border, and EI was determined as mean gray-scale value (0–255 arbitrary units: AU) from the mCSA region of interest. Subcutaneous fat thickness (cm) was measured at three locations: the distance from the superficial aponeurosis to the skin at 50% of the midpoint of the muscle belly, and the lateral and medial ends of the muscle belly. To account for differences in subcutaneous fat between participants and sexes, EI was normalized to subcutaneous fat by dividing EI by the average subcutaneous fat thickness of the three locations as indicated on Fig 1. Our laboratory has previously reported ultrasound image analysis reliability from intra-class correlation coefficients ranging from 0.98–0.99 for quadriceps femoris in ImageJ [29].

Statistical analyses

All data are reported as mean±SD, unless otherwise noted. All data are available in the supplemental file (S2 File). Three separate three-way 2x2x4 [sex (male vs. female) x condition (BFR vs. CON) x time (PRE vs. IMM-POST vs. 30-POST vs. 60-POST)] repeated measures analyses of variance (ANOVA) were conducted to assess differences in mCSA, MT, EI, and normalized EI for each muscle (VM, VL, and RF). A separate three-way [sex x condition x time (set 1 vs. set 2 vs. set 3 vs. set 4)] ANOVA assessed changes in RPE. If a significant interaction was identified, follow-up analyses of additional 2-way or 1-way ANOVAs, t-tests and post-hoc analyses with Bonferroni corrections were conducted. Additionally, an independent t-test was conducted to any descriptive characteristic differences between the sexes. Partial eta square (η_p²) effect sizes were generated and interpreted as trivial (<0.01), small (0.01–0.06), moderate (0.06–0.14), or large (>0.14) [30] effects. All analyses were performed in SPSS v. 27 (IBM, Armonk, NY, USA). Data were considered significant with p<0.05.

Results

Characteristic differences between males and females

Males were significantly taller (mean difference = 0.10 m; percent difference = 6.1%; p = 0.001) and heavier (mean difference = 15.1 kg; percent difference = 21.5%; p<0.001) than the female participants, yet similar in age (p = 0.95) and body mass index (p = 0.117). There was no significant difference between sexes for BFR pressure (males: 183.0±16.2 mmHg; females: 175.7±17.2 mmHg; p = 0.30). The average total occlusion time including inflation and exercise was 9.07±0.97 min with no difference between sexes (p = 0.681).

Muscle cross-sectional area

There was no 3-way interaction in the VM (p = 0.85, η_p² = 0.012) or the RF (p = 0.73, η_p² = 0.019) (Fig 2A). There were also no 2-way (condition x time, sex x condition, or time x sex) interactions in the VM or the RF. Furthermore, there were no main effects for condition or time in either the RF or VM (all p>0.05). There was, however, a main effect for sex (p<0.001, η_p² = 0.481) as males (23.66±4.11 cm²) had larger VM mCSA than females (16.78±3.29 cm²). Yet RF mCSA was similar (p = 0.184, η_p² = 0.079) between sexes (males: 12.74 ± 2.49 cm²; females: 11.50 ± 1.81 cm²).

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Fig 2.

Changes in muscle cross-sectional area (a), muscle thickness (b), echo intensity (c), and subcutaneous fat-normalized echo intensity (d). Data represent mean±SE (males: black lines; females: grey lines; BFR: solid line; CON: dashed line). SE: Standard error. ^#significant difference between sex collapsed across condition and time; ^##significant differences between sex for BFR only; *significant differences between conditions at indicated timepoint collapsed across sex; ^†significant difference between conditions for males at indicated timepoint; ‡significant difference between conditions for females only; §significant difference between timepoints.

https://doi.org/10.1371/journal.pone.0278540.g002

In the VL, there was a 3-way interaction for mCSA (p = 0.025, η_p² = 0.131). When the full model was decomposed and split by sex, there was neither a 2-way (condition x time) interaction (p = 0.811, η_p² = 0.028) nor was there a main effect for time or condition (p = 0.075–0.253) in the females. For males, there was a 2-way (condition x time) interaction (p = 0.008, η_p² = 0.298), yet the decomposed interaction revealed no changes across time in either condition (BFR: p = 0.358, η_p² = 0.092; CON: p = 0.056, η_p² = 0.202). At IMM-POST, BFR was significantly greater than CON by 3.60±4.54 cm² (p = 0.019). All other timepoints were similar between conditions (p = 0.442–0.871). Additionally, when the 3-way interaction was split by condition, the BFR condition indicated no 2-way (sex x time) interaction (p = 0.384, η_p² = 0.045), but there was a main effect for sex (p<0.001, η_p² = 0.527) as males (34.68±5.2 cm²) had larger VL mCSA than females (24.86±4.48 cm²). In CON, there also was a 2-way (sex x time) interaction for VL mCSA (p = 0.047, η_p² = 0.113). Follow-up analyses revealed no changes across time for males (p = 0.056, η_p² = 0.20) or females (p = 0.358, η_p² = 0.092). However, collapsed across time for CON, males (33.77±6.54 cm²) had larger (p<0.001) VL mCSAs than females (23.90±3.83 cm²). There were no sex x condition interactions at PRE (p = 0.760, η_p² = 0.004), IMM-POST (p = 0.103, η_p² = 0.116), 30-POST (p = 0.242, η_p² = 0.062), and 60-POST (p = 0.655, η_p² = 0.009). Collapsed across condition, there was a main effect for sex at all timepoints as males had larger VL mCSAs than females (mean difference±SD; all p<0.001, PRE = 10.1±6.84 cm²; IMM-POST = 9.40±2.14 cm²; 30-POST = 9.49±7.03 cm²; 60-POST = 10.39±7.47 cm²).

Muscle thickness

For MT (Fig 2B), there were no significant 3-way interactions (VM: p = 0.207, η_p² = 0.066; VL: p = 0.300, η_p² = 0.013; RF: p = 0.132, η_p² = 0.083), nor were there any significant 2-way interactions (VM range: p = 0.14–0.49; VL range: p = 0.41–0.86; RF range: p = 0.22–0.95). There was a main effect for sex in the VL (p = 0.001, η_p² = 0.384) as males (2.51±0.27 cm) had larger MT than females (2.12±0.25 cm). Males and females had similar MT in the VM (males: 3.39±0.53 cm; females: 3.09±0.42 cm; p = 0.130, η_p² = 0.101) and RF (males: 2.24±0.33 cm; females: 2.12±0.26 cm; p = 0.353, η_p² = 0.039). There were no additional main effects for condition (VM: p = 0.138, η_p² = 0.097; VL: p = 0.956, η_p²<0.001; RF: p = 0.089, η_p² = 0.126) nor time (VM: p = 0.185, η_p² = 0.070; VL: p = 0.069, η_p² = 0.101; RF: p = 0.642, η_p² = 0.025).

Echo intensity

For EI (Fig 2C), there were no 3-way interactions (VM: p = 0.36, η_p² = 0.047; VL: p = 0.84, η_p² = 0.012; RF: p = 0.88, η_p² = 0.010). However, there was a condition x time interaction in the VM (p = 0.049, η_p² = 0.11) when collapsed across sex. Also, there was a main effect for sex in the VM (p = 0.036, η_p² = 0.18) as females (83.8±12.6 AU) had greater EI than males (75.7±6.9 AU) collapsed across time and condition. The decomposed condition x time model indicated no change across time for CON (p = 0.79, η_p² = 0.015). But there was a main effect for time for BFR (p = 0.002, η_p² = 0.19) as 30-POST (77.37±11.2 AU) was less than both PRE (83.28±10.3 AU, p<0.001) and IMM-POST (81.9±9.9 AU, p = 0.016). Further, EI in the VM during BFR at PRE was significantly greater than CON at PRE (mean difference = 4.8±7.4 AU, p = 0.006) with no other differences between timepoints for conditions (p-range = 0.18–0.28). There were no additional 2-way interactions (sex x condition: p = 0.051, η_p² = 0.162 and time x sex: p = 0.396, η_p² = 0.050) in the VM.

There were no 2-way interactions in the VL (sex x condition: p = 0.86, η_p² = 0.001; time x sex: p = 0.74, η_p² = 0.019, condition x time: p = 0.64, η_p² = 0.025) nor main effects for condition (p = 0.24, η_p² = 0.063) or time (p = 0.15, η_p² = 0.078). There was a main effect for sex (p<0.001, η_p² = 0.44) as females (80.4±10.2 AU) had greater VL EI than males (64.6±9.7 AU).

Lastly, there was a sex x condition interaction in the RF (p = 0.014, η_p² = 0.25) but no other 2-way interactions (time x sex: p = 0.67, η_p² = 0.023, condition x time: p = 0.77, η_p² = 0.017) nor was there a main effect for time (p = 0.45, η_p² = 0.039). Decomposition of the sex x condition interaction in the RF indicated that females had greater EI during BFR (mean difference = 16.3±4.3 AU, p<0.001) but not CON (mean difference = 9.41±4.6 AU, p = 0.054). For the male participants, there were no differences between conditions (p = 0.35). While for the females, RF EI was greater in BFR (90.4±10.5 AU) than CON (85.4±11.2 AU, p = 0.016).

For EI_NORM (Fig 2D), there were no 3-way interactions (VM: p = 0.59, η_p² = 0.03; VL: p = 0.74, η_p² = 0.18; RF: p = 0.33, η_p² = 0.02) nor any 2-way interactions (VM range: p = 0.051–0.23, VL range: p = 0.62–0.85, RF range: p = 0.49–0.67). There were also no main effects for condition (VM: p = 0.23, η_p² = 0.07; VL: p = 0.63, η_p² = 0.01; RF: p = 0.99, η_p²<0.001) nor time (VM: p = 0.20, η_p² = 0.07; VL: p = 0.27, η_p² = 0.06; RF: p = 0.27, η_p² = 0.06). Yet there was a main effect for sex in each muscle (VM: p = 0.005, η_p² = 0.31; VL: p = 0.006, η_p² = 0.29; RF: p = 0.015, η_p² = 0.24) as males had greater EI_NORM (VM: 151.9±57.6 AU; VL: 92.4±43.6 AU, RF: 162.3±71.4 AU) than females (VM: 86.9±46.9 AU; VL: 53.9±20.9 AU; RF: 92.9±56.9 AU).

Rating of perceived exertion

There was no 3-way interaction (sex x condition x time) (p = 0.075, η_p² = 0.099), and no condition x sex (p = 0.622, η_p² = 0.011), or time x sex (p = 0.783, η_p² = 0.016) interactions. However, there was a 2-way interaction for condition x time (p<0.001, η_p² = 0.499), collapsed by sex (Fig 3). Subsequent analyses determined RPE was similar over time for CON (p = 0.144, η_p² = 0.075). In BFR there was a main effect for time (p<0.001, η_p² = 0.579), as set 3 (3.79±1.10 AU) was significantly greater than set 1 (2.79±0.83 AU, p<0.001) and set 2 (3.08±0.88 AU, p<0.001). Set 4 (3.96±1.27 AU) was significantly greater than sets 1 (p<0.001) and 2 (p<0.001). Sets 1 and 2 (p = 0.097) and sets 3 and 4 (p = 0.970) were similar.

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Fig 3. Muscle rating of perceived exertion between conditions and time.

Data represent mean±SD and collapsed across sex (BFR: black bars, CON: grey bars). SD: Standard deviation. *significant differences between conditions at indicated timepoint, collapsed across sex; §significant difference between timepoints.

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Discussion

The purposes of this study were to assess changes in mCSA, MT, and EI of the three superficial quadriceps femoris muscles after a knee rehabilitation exercise performed with and without BFR between males and females. The main finding of this study was that there were no significant changes in muscle size (mCSA or MT) from PRE values in either condition or sex despite greater RPE in the latter sets with BFR. However, BFR induced an approximately 7.6% difference compared to CON in VL mCSA for males at IMM-POST. Additionally, EI was influenced at some time points following the BFR treatment for both sexes and may represent a fluid shift 30 minutes after exercise in the VM. Females had greater EI than males in the VM and VL. However, there were no changes in EI_NORM, although males had greater EI_NORM than females collapsed across condition and time. Independent of sex, all participants reported greater exertion in the latter sets of the BFR condition.

Despite the recent rise in the amount of studies utilizing BFR within a rehabilitation setting [19, 20, 31], there remains a lack of evidence that demonstrates the acute muscular responses to specific rehabilitation exercises performed with BFR. The current study’s results presented a temporary increase in mCSA at IMM-POST in males which may have been caused by the BFR quad sets, but this was a modest 4.0% and insufficient to be significantly greater than any other time point. These results contrast with previous studies that have identified significant changes in muscle size variables (MT and mCSA) of 10.7–12.6% from PRE to after exercise following knee extensions performed with BFR [10–12]. However, the exercises used included concentric, low-load (20–30%) voluntary contractions at varying inflation pressures (140 mmHg) or relative percentages [50% arterial occlusion pressure (AOC)]. BFR has been traditionally performed with low-loads ranging from 20–30% of one-repetition maximum (1-RM) [10, 12]. It is possible the quad sets exercise performed against bodyweight with 80% AOC or without BFR was an insufficient stressor to acutely change muscle size, suggesting load may be required to elicit change. The present results indicated there was no significant change in MT for any muscle following the quad sets exercise with or without BFR. Similarly, Park et al. [32] reported no change in MT of the VL 0, 5, or 10 minutes after unloaded passive knee extensions performed with and without BFR applied. Despite the differences in body position (supine v. seated) and exercise (quad sets v. passive knee extensions), the results of the present study align with the conclusion of Park et al. [32], in that a stimulus of no load BFR is insufficient to result in muscle swelling in healthy participants. Expected differences existed between males and females VL MT and mCSA at all time points. The differences in quadriceps femoris muscle size between males and females has been previously documented for VL mCSA [33]. The lack of differences between sexes in the RF mCSA has been also reported by Myers et al. [34].

In the present study, the change in EI was only evident in the VM which may indicate the level of muscular involvement during a quad set contraction is greater in the VM than the other quadriceps muscles [35]. This concept is supported by the work of Gryzlo et al., as the VM and VL had greater electromyographic amplitudes than the RF during a shortened knee extension moving from 15 degrees of knee flexion to 0 degrees of knee flexion, similar to a quad set [36]. It is interesting to note that there was no change in EI from PRE to IMM-POST in the BFR condition, rather, the difference was indicated at 30-POST only in the VM. BFR can result in greater hemodynamic responses versus low-load non-BFR exercise [11, 15]. Previous methodology suggests resting supine prior to musculoskeletal area measurements as body position could influence fluid shifts [37], however, the predominant literature have indicated no effect of rest time on EI [24, 38, 39]. This may suggest that the change in the VM as presented in the present study may have been driven by some other physiological mechanism such as the intervention and not due any positional shift. Similarly, acute changes in EI have been postulated to be representative of fluid movement within the region [10, 13], as an acute stimulus cannot induce immediate structural changes. Collectively, females have been shown to have greater EI of the quadriceps femoris when compared to males [30]. In the present study, there were no changes in EI_NORM across time or condition. This is interesting as BFR has been reported to result in greater hemodynamic responses versus low-load non-BFR exercise [11, 15], suggesting BFR could reduce EI values following exercise. Following low-load exercise an increase in EI of the biceps brachii was shown by Hill et al. with and without BFR [40] and in the VL and RF after non-occluded knee extensions by Muddle et al. [41], while Wong et al. noted inconsistent changes in the biceps brachii after BFR exercise [42]. Due to the differences in methodologies between these and other studies and the inconsistent findings of the present study to go along with those presented by previous research, there does not appear to be a consensus on what happens to EI after BFR exercise [43]. Males had significantly greater EI_NORM than females in each muscle by ~70%, which opposes when EI is reported without subcutaneous fat consideration [33]. This could be due to males in general having lower EI than females and less subcutaneous fat on the anterior thigh. These shifts may be influenced by factors such as exercise type (isometric versus dynamic constant external resistance) and may differ between skeletal muscles. Future research should continue to investigate the response of EI to BFR exercise and attempt to elucidate what it represents, physiologically. Lastly, it is important to note that the differences EI observed in the present compared to previous research could be due to factors such as subcutaneous fat normalization and differences in ultrasound equipment and settings [29, 33].

The participants reported BFR to result in higher perceived exertion than CON by 1.86 AU (~120%) across all sets, which is in line with pervious literature [11, 15]. Specifically, Hackney et al. reported an RPE increase of ~6.0 AU from baseline to the peak response during BFR knee extensions [11]. Poton and Polito reported the highest RPE from low-intensity BFR resistance exercise over high- or low-intensity resistance exercise without BFR [15]. Potentially, the pressure of the occlusion cuff alone could have resulted in greater discomfort and exertion than the CON condition, although a 10-cm cuff width has been reported to be the least painful [3, 22]. Despite the increase in the RPE in the latter sets that included BFR in the present study, the lack of muscular swelling (MT and mCSA) suggests the unloaded contractions may not have been a sufficient stimulus, even if the participants perceived them to be more difficult.

Limitations of this study include that the participants did not have physical or functional deficits, such as injury or atrophy, to elicit the intended response to the unloaded quad sets. Further, the differences in ultrasound equipment and may limit our ability to compare EI findings across studies. Additionally, the physiologic meaning of changes to EI have been interpreted in vastly different scenarios and settings, which warrants further evaluation and perhaps higher-level validity (i.e., comparison to fat or fluid shifts as evaluated by magnetic resonance imaging of near-infrared spectroscopy), which the present study did not pursue. To best elucidate the potential of BFR in clinical populations, future directions of similar investigations may need to include the manipulation of resistance training related variables (e.g., load, repetitions, tempo) with BFR in an injured and rehabilitating population. Modified loaded rehabilitation exercises should be explored, such as single leg raises with ankle weights. Future efforts should also continue to investigate the differences between sexes in response to BFR exercise, especially as females have been overall greatly underrepresented in the exercise physiology literature.

Conclusion

Overall, the present study provides insight to the muscular response of males and females completing isometric quadriceps contractions, or quad sets, with and without BFR. Perceived exertion was greater towards the end of exercise sessions, although there was largely a lack of effect from BFR quad sets on significant changes across time in mCSA and MT of the VL and VM. No acute fluid shifts were indicated as there were no changes in EI, normalized to subcutaneous fat, in any of the muscles in either condition. Some acute fluid shifts were indicated as the corrected EI of the VM changed following BFR, yet males and females responded similarly under both conditions. The RF was not influenced in any way for either sex or condition. As quad sets have been traditionally utilized only in clinical populations following lower extremity surgeries, it is possible that clinical populations may have differential responses than the ones observed in the present study, which warrants future research.

Supporting information

S1 File. Timeline of study procedures (S1 Fig 1) and exercise set-up with blood flow restriction cuff applied (S1 Fig 1).

https://doi.org/10.1371/journal.pone.0278540.s001

(PDF)

S2 File. All available data of the study in csv format.

https://doi.org/10.1371/journal.pone.0278540.s002

(CSV)

References

1. Loenneke JP, Wilson JM, Marín PJ, Zourdos MC, Bemben MG. Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol. 2012;112: 1849–1859. pmid:21922259
- View Article
- PubMed/NCBI
- Google Scholar
2. Lixandrão ME, Ugrinowitsch C, Berton R, Vechin FC, Conceição MS, Damas F, et al. Magnitude of Muscle Strength and Mass Adaptations Between High-Load Resistance Training Versus Low-Load Resistance Training Associated with Blood-Flow Restriction: A Systematic Review and Meta-Analysis. Sports Med. 2018;48: 361–378. pmid:29043659
- View Article
- PubMed/NCBI
- Google Scholar
3. Patterson SD, Hughes L, Warmington S, Burr J, Scott BR, Owens J, et al. Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Front Physiol. 2019;10: 533. pmid:31156448
- View Article
- PubMed/NCBI
- Google Scholar
4. Pearson SJ, Hussain SR. A Review on the Mechanisms of Blood-Flow Restriction Resistance Training-Induced Muscle Hypertrophy. Sports Med. 2015;45: 187–200. pmid:25249278
- View Article
- PubMed/NCBI
- Google Scholar
5. Buckner SL, Dankel SJ, Mattocks KT, Jessee MB, Mouser JG, Counts BR, et al. Differentiating swelling and hypertrophy through indirect assessment of muscle damage in untrained men following repeated bouts of resistance exercise. Eur J Appl Physiol. 2017;117: 213–224. pmid:28012037
- View Article
- PubMed/NCBI
- Google Scholar
6. Loenneke JP, Fahs CA, Rossow LM, Abe T, Bemben MG. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Med Hypotheses. 2012;78: 151–154. pmid:22051111
- View Article
- PubMed/NCBI
- Google Scholar
7. Yasuda T, Loenneke JP, Thiebaud RS, Abe T. Effects of blood flow restricted low-intensity concentric or eccentric training on muscle size and strength. PLoS One. 2012;7: e52843. pmid:23300795
- View Article
- PubMed/NCBI
- Google Scholar
8. Manini TM, Clark BC. Blood flow restricted exercise and skeletal muscle health. Exerc Sport Sci Rev. 2009;37: 78–85. pmid:19305199
- View Article
- PubMed/NCBI
- Google Scholar
9. Hwang PS, Willoughby DS. Mechanisms Behind Blood Flow-Restricted Training and its Effect Toward Muscle Growth. J Strength Cond Res. 2019;33 Suppl 1: S167–S179. pmid:30011262
- View Article
- PubMed/NCBI
- Google Scholar
10. Bell ZW, Abe T, Wong V, Spitz RW, Viana RB, Chatakondi RN, et al. Muscle swelling following blood flow-restricted exercise does not differ between cuff widths in the proximal or distal portions of the upper leg. Clin Physiol Funct Imaging. 2020;40: 269–276. pmid:32319156
- View Article
- PubMed/NCBI
- Google Scholar
11. Hackney KJ, Olson BM, Schmidt AJ, Nelson AH, Zacharias EL. Acute Muscular, Metabolic, Cardiovascular, and Perceptual Responses to Low Cuff Pressure-small Cuff Width Blood Flow Restricted Exercise Prescription. J Nov Physiother. 2016;6.
- View Article
- Google Scholar
12. Young TR, Duncan BT, Cook SB. Evaluation of muscle thickness of the vastus lateralis by ultrasound imaging following blood flow restricted resistance exercise. Clin Physiol Funct Imaging. 2021;41: 376–384. pmid:33884750
- View Article
- PubMed/NCBI
- Google Scholar
13. Jenkins NDM. Are Resistance Training-Mediated Decreases in Ultrasound Echo Intensity Caused by Changes in Muscle Composition, or Is There an Alternative Explanation? Ultrasound Med Biol. 2016;42: 3050–3051. pmid:27590097
- View Article
- PubMed/NCBI
- Google Scholar
14. Haddock B, Hansen SK, Lindberg U, Nielsen JL, Frandsen U, Aagaard P, et al. Exercise-induced fluid shifts are distinct to exercise mode and intensity: a comparison of blood flow-restricted and free-flow resistance exercise. J Appl Physiol (1985). 2021;130: 1822–1835. pmid:33914664
- View Article
- PubMed/NCBI
- Google Scholar
15. Poton R, Polito MD. Hemodynamic response to resistance exercise with and without blood flow restriction in healthy subjects. Clin Physiol Funct Imaging. 2016;36: 231–236. pmid:25431280
- View Article
- PubMed/NCBI
- Google Scholar
16. Forrester LA, Schweppe EA, Popkin CA. Variability in rehabilitation protocols following pediatric anterior cruciate ligament (ACL) reconstruction. The Physician and Sportsmedicine. 2019;47: 448–454. pmid:31122097
- View Article
- PubMed/NCBI
- Google Scholar
17. Ito Y, Aoki T, Sato T, Oishi K, Ishii K. Comparison of quadriceps setting strength and knee extension strength tests to evaluate lower limb muscle strength based on health-related physical fitness values in elderly people. BMJ Open Sport Exerc Med. 2020;6: e000753. pmid:32642071
- View Article
- PubMed/NCBI
- Google Scholar
18. Makhni EC, Crump EK, Steinhaus ME, Verma NN, Ahmad CS, Cole BJ, et al. Quality and Variability of Online Available Physical Therapy Protocols From Academic Orthopaedic Surgery Programs for Anterior Cruciate Ligament Reconstruction. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2016;32: 1612–1621. pmid:27032604
- View Article
- PubMed/NCBI
- Google Scholar
19. Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, et al. Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial. Sports Med. 2019;49: 1787–1805. pmid:31301034
- View Article
- PubMed/NCBI
- Google Scholar
20. Iversen E, Røstad V, Larmo A. Intermittent blood flow restriction does not reduce atrophy following anterior cruciate ligament reconstruction. Journal of Sport and Health Science. 2016;5: 115–118. pmid:30356481
- View Article
- PubMed/NCBI
- Google Scholar
21. Lambert B, Hedt CA, Jack RA, Moreno M, Delgado D, Harris JD, et al. Blood Flow Restriction Therapy Preserves Whole Limb Bone and Muscle Following ACL Reconstruction. Orthopaedic Journal of Sports Medicine. 2019;7: 2325967119S00196.
- View Article
- Google Scholar
22. Loenneke JP, Fahs CA, Rossow LM, Sherk VD, Thiebaud RS, Abe T, et al. Effects of cuff width on arterial occlusion: implications for blood flow restricted exercise. Eur J Appl Physiol. 2012;112: 2903–2912. pmid:22143843
- View Article
- PubMed/NCBI
- Google Scholar
23. Pageaux B. Perception of effort in Exercise Science: Definition, measurement and perspectives. European Journal of Sport Science. 2016;16: 885–894. pmid:27240002
- View Article
- PubMed/NCBI
- Google Scholar
24. Arroyo E, Stout JR, Beyer KS, Church DD, Varanoske AN, Fukuda DH, et al. Effects of supine rest duration on ultrasound measures of the vastus lateralis. Clinical Physiology and Functional Imaging. 2018;38: 155–157. pmid:27981803
- View Article
- PubMed/NCBI
- Google Scholar
25. Ahtiainen JP, Hoffren M, Hulmi JJ, Pietikäinen M, Mero AA, Avela J, et al. Panoramic ultrasonography is a valid method to measure changes in skeletal muscle cross-sectional area. Eur J Appl Physiol. 2010;108: 273–279. pmid:19777252
- View Article
- PubMed/NCBI
- Google Scholar
26. Garcia SA, Moffit TJ, Vakula MN, Holmes SC, Montgomery MM, Pamukoff DN. Quadriceps Muscle Size, Quality, and Strength and Self-Reported Function in Individuals With Anterior Cruciate Ligament Reconstruction. J Athl Train. 2020;55: 246–254. pmid:31951147
- View Article
- PubMed/NCBI
- Google Scholar
27. Soderberg GL, Cook TM. An electromyographic analysis of quadriceps femoris muscle setting and straight leg raising. Phys Ther. 1983;63: 1434–1438. pmid:6611665
- View Article
- PubMed/NCBI
- Google Scholar
28. van Melick N, Meddeler BM, Hoogeboom TJ, Nijhuis-van der Sanden MWG, van Cingel REH. How to determine leg dominance: The agreement between self-reported and observed performance in healthy adults. PLoS One. 2017;12: e0189876. pmid:29287067
- View Article
- PubMed/NCBI
- Google Scholar
29. Cleary CJ, Nabavizadeh O, Young KL, Herda AA. Skeletal muscle analysis of panoramic ultrasound is reliable across multiple raters. PLOS ONE. 2022;17: e0267641. pmid:35500010
- View Article
- PubMed/NCBI
- Google Scholar
30. Lakens D. Calculating and reporting effect sizes to facilitate cumulative science: a practical primer for t-tests and ANOVAs. Front Psychol. 2013;4.
- View Article
- Google Scholar
31. Curran MT, Bedi A, Mendias CL, Wojtys EM, Kujawa MV, Palmieri-Smith RM. Blood Flow Restriction Training Applied With High-Intensity Exercise Does Not Improve Quadriceps Muscle Function After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial. Am J Sports Med. 2020;48: 825–837. pmid:32167837
- View Article
- PubMed/NCBI
- Google Scholar
32. Park J, Stanford DM, Buckner SL, Jessee MB. The acute muscular response to passive movement and blood flow restriction. Clin Physiol Funct Imaging. 2020;40: 351–359. pmid:32511829
- View Article
- PubMed/NCBI
- Google Scholar
33. Stock MS, Oranchuk DJ, Burton AM, Phan DC. Age-, sex-, and region-specific differences in skeletal muscle size and quality. Appl Physiol Nutr Metab. 2020;45: 1253–1260. pmid:32450045
- View Article
- PubMed/NCBI
- Google Scholar
34. Myers H, Davis A, Lazicki R, Martinez C, Black D, Butler RJ. Sex differences in rectus femoris morphology across different knee flexion positions. Int J Sports Phys Ther. 2013;8: 84–90. pmid:23593545
- View Article
- PubMed/NCBI
- Google Scholar
35. Cerny K. Vastus Medialis Oblique/Vastus Lateralis Muscle Activity Ratios for Selected Exercises in Persons With and Without Patellofemoral Pain Syndrome. Physical Therapy. 1995;75: 672–683. pmid:7644571
- View Article
- PubMed/NCBI
- Google Scholar
36. Gryzlo SM, Patek RM, Pink M, Perry J. Electromyographic analysis of knee rehabilitation exercises. J Orthop Sports Phys Ther. 1994;20: 36–43. pmid:8081408
- View Article
- PubMed/NCBI
- Google Scholar
37. Berg HE, Tedner B, Tesch PA. Changes in lower limb muscle cross-sectional area and tissue fluid volume after transition from standing to supine. Acta Physiologica Scandinavica. 1993;148: 379–385. pmid:8213193
- View Article
- PubMed/NCBI
- Google Scholar
38. Lopez P, Pinto MD, Pinto RS. Does Rest Time before Ultrasonography Imaging Affect Quadriceps Femoris Muscle Thickness, Cross-Sectional Area and Echo Intensity Measurements? Ultrasound in Medicine & Biology. 2019;45: 612–616. pmid:30471782
- View Article
- PubMed/NCBI
- Google Scholar
39. Varanoske AN, Coker NA, Johnson B-ADI, Belity T, Wells AJ. Muscle Quality, Measured by Ultrasound-Derived Corrected Echo Intensity, Does not Affect Changes in Cross-sectional Area of the Vastus Lateralis Following Recumbent Rest. Journal of Diagnostic Medical Sonography. 2021;37: 157–168.
- View Article
- Google Scholar
40. Hill EC, Housh TJ, Smith CM, Keller JL, Anders JPV, Schmidt RJ, et al. Acute changes in muscle thickness, edema, and blood flow are not different between low-load blood flow restriction and non-blood flow restriction. Clin Physiol Funct Imaging. 2021;41: 452–460. pmid:34192417
- View Article
- PubMed/NCBI
- Google Scholar
41. Muddle TWD, Magrini MA, Colquhoun RJ, Luera MJ, Tomko PM, Jenkins NDM. Impact of Fatiguing, Submaximal High- vs. Low-Torque Isometric Exercise on Acute Muscle Swelling, and Echo Intensity in Resistance-Trained Men. J Strength Cond Res. 2019;33: 1007–1019. pmid:30789573
- View Article
- PubMed/NCBI
- Google Scholar
42. Wong V, Abe T, Chatakondi RN, Bell ZW, Spitz RW, Dankel SJ, et al. The influence of biological sex and cuff width on muscle swelling, echo intensity, and the fatigue response to blood flow restricted exercise. J Sports Sci. 2019;37: 1865–1873. pmid:30945606
- View Article
- PubMed/NCBI
- Google Scholar
43. Wong V, Spitz RW, Bell ZW, Viana RB, Chatakondi RN, Abe T, et al. Exercise induced changes in echo intensity within the muscle: a brief review. J Ultrasound. 2020;23: 457–472. pmid:31925731
- View Article
- PubMed/NCBI
- Google Scholar

[ref1] 1. Loenneke JP, Wilson JM, Marín PJ, Zourdos MC, Bemben MG. Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol. 2012;112: 1849–1859. pmid:21922259
View Article
PubMed/NCBI
Google Scholar

[2] View Article

[3] PubMed/NCBI

[4] Google Scholar

[ref2] 2. Lixandrão ME, Ugrinowitsch C, Berton R, Vechin FC, Conceição MS, Damas F, et al. Magnitude of Muscle Strength and Mass Adaptations Between High-Load Resistance Training Versus Low-Load Resistance Training Associated with Blood-Flow Restriction: A Systematic Review and Meta-Analysis. Sports Med. 2018;48: 361–378. pmid:29043659
View Article
PubMed/NCBI
Google Scholar

[6] View Article

[7] PubMed/NCBI

[8] Google Scholar

[ref3] 3. Patterson SD, Hughes L, Warmington S, Burr J, Scott BR, Owens J, et al. Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Front Physiol. 2019;10: 533. pmid:31156448
View Article
PubMed/NCBI
Google Scholar

[10] View Article

[11] PubMed/NCBI

[12] Google Scholar

[ref4] 4. Pearson SJ, Hussain SR. A Review on the Mechanisms of Blood-Flow Restriction Resistance Training-Induced Muscle Hypertrophy. Sports Med. 2015;45: 187–200. pmid:25249278
View Article
PubMed/NCBI
Google Scholar

[14] View Article

[15] PubMed/NCBI

[16] Google Scholar

[ref5] 5. Buckner SL, Dankel SJ, Mattocks KT, Jessee MB, Mouser JG, Counts BR, et al. Differentiating swelling and hypertrophy through indirect assessment of muscle damage in untrained men following repeated bouts of resistance exercise. Eur J Appl Physiol. 2017;117: 213–224. pmid:28012037
View Article
PubMed/NCBI
Google Scholar

[18] View Article

[19] PubMed/NCBI

[20] Google Scholar

[ref6] 6. Loenneke JP, Fahs CA, Rossow LM, Abe T, Bemben MG. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Med Hypotheses. 2012;78: 151–154. pmid:22051111
View Article
PubMed/NCBI
Google Scholar

[22] View Article

[23] PubMed/NCBI

[24] Google Scholar

[ref7] 7. Yasuda T, Loenneke JP, Thiebaud RS, Abe T. Effects of blood flow restricted low-intensity concentric or eccentric training on muscle size and strength. PLoS One. 2012;7: e52843. pmid:23300795
View Article
PubMed/NCBI
Google Scholar

[26] View Article

[27] PubMed/NCBI

[28] Google Scholar

[ref8] 8. Manini TM, Clark BC. Blood flow restricted exercise and skeletal muscle health. Exerc Sport Sci Rev. 2009;37: 78–85. pmid:19305199
View Article
PubMed/NCBI
Google Scholar

[30] View Article

[31] PubMed/NCBI

[32] Google Scholar

[ref9] 9. Hwang PS, Willoughby DS. Mechanisms Behind Blood Flow-Restricted Training and its Effect Toward Muscle Growth. J Strength Cond Res. 2019;33 Suppl 1: S167–S179. pmid:30011262
View Article
PubMed/NCBI
Google Scholar

[34] View Article

[35] PubMed/NCBI

[36] Google Scholar

[ref10] 10. Bell ZW, Abe T, Wong V, Spitz RW, Viana RB, Chatakondi RN, et al. Muscle swelling following blood flow-restricted exercise does not differ between cuff widths in the proximal or distal portions of the upper leg. Clin Physiol Funct Imaging. 2020;40: 269–276. pmid:32319156
View Article
PubMed/NCBI
Google Scholar

[38] View Article

[39] PubMed/NCBI

[40] Google Scholar

[ref11] 11. Hackney KJ, Olson BM, Schmidt AJ, Nelson AH, Zacharias EL. Acute Muscular, Metabolic, Cardiovascular, and Perceptual Responses to Low Cuff Pressure-small Cuff Width Blood Flow Restricted Exercise Prescription. J Nov Physiother. 2016;6.
View Article
Google Scholar

[42] View Article

[43] Google Scholar

[ref12] 12. Young TR, Duncan BT, Cook SB. Evaluation of muscle thickness of the vastus lateralis by ultrasound imaging following blood flow restricted resistance exercise. Clin Physiol Funct Imaging. 2021;41: 376–384. pmid:33884750
View Article
PubMed/NCBI
Google Scholar

[45] View Article

[46] PubMed/NCBI

[47] Google Scholar

[ref13] 13. Jenkins NDM. Are Resistance Training-Mediated Decreases in Ultrasound Echo Intensity Caused by Changes in Muscle Composition, or Is There an Alternative Explanation? Ultrasound Med Biol. 2016;42: 3050–3051. pmid:27590097
View Article
PubMed/NCBI
Google Scholar

[49] View Article

[50] PubMed/NCBI

[51] Google Scholar

[ref14] 14. Haddock B, Hansen SK, Lindberg U, Nielsen JL, Frandsen U, Aagaard P, et al. Exercise-induced fluid shifts are distinct to exercise mode and intensity: a comparison of blood flow-restricted and free-flow resistance exercise. J Appl Physiol (1985). 2021;130: 1822–1835. pmid:33914664
View Article
PubMed/NCBI
Google Scholar

[53] View Article

[54] PubMed/NCBI

[55] Google Scholar

[ref15] 15. Poton R, Polito MD. Hemodynamic response to resistance exercise with and without blood flow restriction in healthy subjects. Clin Physiol Funct Imaging. 2016;36: 231–236. pmid:25431280
View Article
PubMed/NCBI
Google Scholar

[57] View Article

[58] PubMed/NCBI

[59] Google Scholar

[ref16] 16. Forrester LA, Schweppe EA, Popkin CA. Variability in rehabilitation protocols following pediatric anterior cruciate ligament (ACL) reconstruction. The Physician and Sportsmedicine. 2019;47: 448–454. pmid:31122097
View Article
PubMed/NCBI
Google Scholar

[61] View Article

[62] PubMed/NCBI

[63] Google Scholar

[ref17] 17. Ito Y, Aoki T, Sato T, Oishi K, Ishii K. Comparison of quadriceps setting strength and knee extension strength tests to evaluate lower limb muscle strength based on health-related physical fitness values in elderly people. BMJ Open Sport Exerc Med. 2020;6: e000753. pmid:32642071
View Article
PubMed/NCBI
Google Scholar

[65] View Article

[66] PubMed/NCBI

[67] Google Scholar

[ref18] 18. Makhni EC, Crump EK, Steinhaus ME, Verma NN, Ahmad CS, Cole BJ, et al. Quality and Variability of Online Available Physical Therapy Protocols From Academic Orthopaedic Surgery Programs for Anterior Cruciate Ligament Reconstruction. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2016;32: 1612–1621. pmid:27032604
View Article
PubMed/NCBI
Google Scholar

[69] View Article

[70] PubMed/NCBI

[71] Google Scholar

[ref19] 19. Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, et al. Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial. Sports Med. 2019;49: 1787–1805. pmid:31301034
View Article
PubMed/NCBI
Google Scholar

[73] View Article

[74] PubMed/NCBI

[75] Google Scholar

[ref20] 20. Iversen E, Røstad V, Larmo A. Intermittent blood flow restriction does not reduce atrophy following anterior cruciate ligament reconstruction. Journal of Sport and Health Science. 2016;5: 115–118. pmid:30356481
View Article
PubMed/NCBI
Google Scholar

[77] View Article

[78] PubMed/NCBI

[79] Google Scholar

[ref21] 21. Lambert B, Hedt CA, Jack RA, Moreno M, Delgado D, Harris JD, et al. Blood Flow Restriction Therapy Preserves Whole Limb Bone and Muscle Following ACL Reconstruction. Orthopaedic Journal of Sports Medicine. 2019;7: 2325967119S00196.
View Article
Google Scholar

[81] View Article

[82] Google Scholar

[ref22] 22. Loenneke JP, Fahs CA, Rossow LM, Sherk VD, Thiebaud RS, Abe T, et al. Effects of cuff width on arterial occlusion: implications for blood flow restricted exercise. Eur J Appl Physiol. 2012;112: 2903–2912. pmid:22143843
View Article
PubMed/NCBI
Google Scholar

[84] View Article

[85] PubMed/NCBI

[86] Google Scholar

[ref23] 23. Pageaux B. Perception of effort in Exercise Science: Definition, measurement and perspectives. European Journal of Sport Science. 2016;16: 885–894. pmid:27240002
View Article
PubMed/NCBI
Google Scholar

[88] View Article

[89] PubMed/NCBI

[90] Google Scholar

[ref24] 24. Arroyo E, Stout JR, Beyer KS, Church DD, Varanoske AN, Fukuda DH, et al. Effects of supine rest duration on ultrasound measures of the vastus lateralis. Clinical Physiology and Functional Imaging. 2018;38: 155–157. pmid:27981803
View Article
PubMed/NCBI
Google Scholar

[92] View Article

[93] PubMed/NCBI

[94] Google Scholar

[ref25] 25. Ahtiainen JP, Hoffren M, Hulmi JJ, Pietikäinen M, Mero AA, Avela J, et al. Panoramic ultrasonography is a valid method to measure changes in skeletal muscle cross-sectional area. Eur J Appl Physiol. 2010;108: 273–279. pmid:19777252
View Article
PubMed/NCBI
Google Scholar

[96] View Article

[97] PubMed/NCBI

[98] Google Scholar

[ref26] 26. Garcia SA, Moffit TJ, Vakula MN, Holmes SC, Montgomery MM, Pamukoff DN. Quadriceps Muscle Size, Quality, and Strength and Self-Reported Function in Individuals With Anterior Cruciate Ligament Reconstruction. J Athl Train. 2020;55: 246–254. pmid:31951147
View Article
PubMed/NCBI
Google Scholar

[100] View Article

[101] PubMed/NCBI

[102] Google Scholar

[ref27] 27. Soderberg GL, Cook TM. An electromyographic analysis of quadriceps femoris muscle setting and straight leg raising. Phys Ther. 1983;63: 1434–1438. pmid:6611665
View Article
PubMed/NCBI
Google Scholar

[104] View Article

[105] PubMed/NCBI

[106] Google Scholar

[ref28] 28. van Melick N, Meddeler BM, Hoogeboom TJ, Nijhuis-van der Sanden MWG, van Cingel REH. How to determine leg dominance: The agreement between self-reported and observed performance in healthy adults. PLoS One. 2017;12: e0189876. pmid:29287067
View Article
PubMed/NCBI
Google Scholar

[108] View Article

[109] PubMed/NCBI

[110] Google Scholar

[ref29] 29. Cleary CJ, Nabavizadeh O, Young KL, Herda AA. Skeletal muscle analysis of panoramic ultrasound is reliable across multiple raters. PLOS ONE. 2022;17: e0267641. pmid:35500010
View Article
PubMed/NCBI
Google Scholar

[112] View Article

[113] PubMed/NCBI

[114] Google Scholar

[ref30] 30. Lakens D. Calculating and reporting effect sizes to facilitate cumulative science: a practical primer for t-tests and ANOVAs. Front Psychol. 2013;4.
View Article
Google Scholar

[116] View Article

[117] Google Scholar

[ref31] 31. Curran MT, Bedi A, Mendias CL, Wojtys EM, Kujawa MV, Palmieri-Smith RM. Blood Flow Restriction Training Applied With High-Intensity Exercise Does Not Improve Quadriceps Muscle Function After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial. Am J Sports Med. 2020;48: 825–837. pmid:32167837
View Article
PubMed/NCBI
Google Scholar

[119] View Article

[120] PubMed/NCBI

[121] Google Scholar

[ref32] 32. Park J, Stanford DM, Buckner SL, Jessee MB. The acute muscular response to passive movement and blood flow restriction. Clin Physiol Funct Imaging. 2020;40: 351–359. pmid:32511829
View Article
PubMed/NCBI
Google Scholar

[123] View Article

[124] PubMed/NCBI

[125] Google Scholar

[ref33] 33. Stock MS, Oranchuk DJ, Burton AM, Phan DC. Age-, sex-, and region-specific differences in skeletal muscle size and quality. Appl Physiol Nutr Metab. 2020;45: 1253–1260. pmid:32450045
View Article
PubMed/NCBI
Google Scholar

[127] View Article

[128] PubMed/NCBI

[129] Google Scholar

[ref34] 34. Myers H, Davis A, Lazicki R, Martinez C, Black D, Butler RJ. Sex differences in rectus femoris morphology across different knee flexion positions. Int J Sports Phys Ther. 2013;8: 84–90. pmid:23593545
View Article
PubMed/NCBI
Google Scholar

[131] View Article

[132] PubMed/NCBI

[133] Google Scholar

[ref35] 35. Cerny K. Vastus Medialis Oblique/Vastus Lateralis Muscle Activity Ratios for Selected Exercises in Persons With and Without Patellofemoral Pain Syndrome. Physical Therapy. 1995;75: 672–683. pmid:7644571
View Article
PubMed/NCBI
Google Scholar

[135] View Article

[136] PubMed/NCBI

[137] Google Scholar

[ref36] 36. Gryzlo SM, Patek RM, Pink M, Perry J. Electromyographic analysis of knee rehabilitation exercises. J Orthop Sports Phys Ther. 1994;20: 36–43. pmid:8081408
View Article
PubMed/NCBI
Google Scholar

[139] View Article

[140] PubMed/NCBI

[141] Google Scholar

[ref37] 37. Berg HE, Tedner B, Tesch PA. Changes in lower limb muscle cross-sectional area and tissue fluid volume after transition from standing to supine. Acta Physiologica Scandinavica. 1993;148: 379–385. pmid:8213193
View Article
PubMed/NCBI
Google Scholar

[143] View Article

[144] PubMed/NCBI

[145] Google Scholar

[ref38] 38. Lopez P, Pinto MD, Pinto RS. Does Rest Time before Ultrasonography Imaging Affect Quadriceps Femoris Muscle Thickness, Cross-Sectional Area and Echo Intensity Measurements? Ultrasound in Medicine & Biology. 2019;45: 612–616. pmid:30471782
View Article
PubMed/NCBI
Google Scholar

[147] View Article

[148] PubMed/NCBI

[149] Google Scholar

[ref39] 39. Varanoske AN, Coker NA, Johnson B-ADI, Belity T, Wells AJ. Muscle Quality, Measured by Ultrasound-Derived Corrected Echo Intensity, Does not Affect Changes in Cross-sectional Area of the Vastus Lateralis Following Recumbent Rest. Journal of Diagnostic Medical Sonography. 2021;37: 157–168.
View Article
Google Scholar

[151] View Article

[152] Google Scholar

[ref40] 40. Hill EC, Housh TJ, Smith CM, Keller JL, Anders JPV, Schmidt RJ, et al. Acute changes in muscle thickness, edema, and blood flow are not different between low-load blood flow restriction and non-blood flow restriction. Clin Physiol Funct Imaging. 2021;41: 452–460. pmid:34192417
View Article
PubMed/NCBI
Google Scholar

[154] View Article

[155] PubMed/NCBI

[156] Google Scholar

[ref41] 41. Muddle TWD, Magrini MA, Colquhoun RJ, Luera MJ, Tomko PM, Jenkins NDM. Impact of Fatiguing, Submaximal High- vs. Low-Torque Isometric Exercise on Acute Muscle Swelling, and Echo Intensity in Resistance-Trained Men. J Strength Cond Res. 2019;33: 1007–1019. pmid:30789573
View Article
PubMed/NCBI
Google Scholar

[158] View Article

[159] PubMed/NCBI

[160] Google Scholar

[ref42] 42. Wong V, Abe T, Chatakondi RN, Bell ZW, Spitz RW, Dankel SJ, et al. The influence of biological sex and cuff width on muscle swelling, echo intensity, and the fatigue response to blood flow restricted exercise. J Sports Sci. 2019;37: 1865–1873. pmid:30945606
View Article
PubMed/NCBI
Google Scholar

[162] View Article

[163] PubMed/NCBI

[164] Google Scholar

[ref43] 43. Wong V, Spitz RW, Bell ZW, Viana RB, Chatakondi RN, Abe T, et al. Exercise induced changes in echo intensity within the muscle: a brief review. J Ultrasound. 2020;23: 457–472. pmid:31925731
View Article
PubMed/NCBI
Google Scholar

[166] View Article

[167] PubMed/NCBI

[168] Google Scholar

Figures

Abstract

Introduction

Materials and methods

Procedures

Participants.

Ultrasound image acquisition.

Exercise protocols.

Ultrasound image analysis

Statistical analyses

Results

Characteristic differences between males and females

Muscle cross-sectional area

Muscle thickness

Echo intensity

Rating of perceived exertion

Discussion

Conclusion

Supporting information

S1 File. Timeline of study procedures (S1 Fig 1) and exercise set-up with blood flow restriction cuff applied (S1 Fig 1).

S2 File. All available data of the study in csv format.

References