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BRIDGING THE GAP-RESEARCH: The effects of knee wraps on weightlifting performance and injury
Abstract
"Bridging the Gap" is a continuing feature of the NSCA Journal. Various topics are presented with companion articles addressing the physiological and/or research basis, as well as the practical applications. In this way, the NSCA Journal continues to bridge the gap between sports researchers and sports practitioners. See page 36 for the practical application of these concepts.
(C) 1990 National Strength and Conditioning Association
... Comparing vastus lateralis and gluteus maximus activity during back squats with and without knee wraps, using knee wraps resulted in increased vastus lateralis and decreased gluteus maximus activations when squatting at 90% 1rM [5]. Although beneficial for weightlifting, knee wraps require specific wrapping techniques [10] and could involve significant occlusion of the knee joint [12]. in addition, the significant changes to hip and knee biomechanics when using knee wraps [5,9], coupled with alterations in vastus lateralis activation [5], could negatively impact on joint stability during weight training programs. ...
... Although little research exists on knee sleeves during weightlifting exercises, knee wraps are a well investigated knee support device. Various studies have found additional mass lifted with knee wraps to be anywhere from 10-13% to 20-25% while squatting to 90° [5,10,12]. Although 1rMs in our study were not performed to a depth of 90°, our comparisons of submaximal squats to both full-depth (120°) and parallel (100°) suggest no 'carry-over' effect would occur at smaller knee angles. ...
... However, this study revealed no increase in mass lifted. in addition, this study and the previous work by Sinclair et al. [18] found no increase in vertical velocity. the lack of differences observed here compared with previous studies' findings for knee wraps [5,10,12] are likely due to differences in the elastic properties of these two materials. it is also important to note knee wraps are worn very tightly around the knee joint [5,12], whereas knee sleeves worn in accordance with the manufacturer's specifications do not provide the same tight fit. ...
Purpose
Knee sleeves have become widely popular in the exercise realm, especially for knee support during back squats. Knee sleeves are successful in providing frontal plane knee support during functional tasks, but have not been investigated in back squats. Knee wraps, a somewhat similar elastic material, provide elastic energy that increases weight lifted during back squats. Thus, it is possible the thick neoprene knee sleeves could prove advantageous for back squats. The purpose of this study was to examine the effects of knee sleeves on weight lifted, knee biomechanics, and muscle activations during back squats.
Methods
Fifteen resistance trained men and women performed 1-repetition maximum (1-RM) squats to full depth and 80% 1-RM to full and parallel depths during two separate randomized sessions: with/without knee sleeves. Three-dimensional motion capture, force platforms, and electromyography recorded knee biomechanics and activations of the rectus femoris, vastus medialis, biceps femoris long head, and gluteus maximus during all squats.
Results
Maximal weight lifted did not improve when using knee sleeves. Frontal plane knee biomechanics did not differ for 1-RM or submaximal squats to either depth between conditions. Knee external rotation moments during descent were larger with sleeves during submaximal squats. Reduced integrated ascent phase gluteus maximus activations occurred during both 1-RM and submaximal squats with knee sleeves.
Conclusions
The results of this study show that wearing knee sleeves does not provide additive effects to weight lifted and do not appear to alter frontal plane mechanics during weighted back squats.
... Specifically, those involved in competitive powerlifting will commonly use compressive material around the knee joint to increase performance and reduce the occurrence of injury during the barbell squat (7). As one of the 3 primary competition movements alongside the barbell bench press and deadlift, these athletes frequently perform squats and similar motions that require large demands on knee flexion that are subsequently associated with compromised knee joints (9,27). Therefore, it is common for competitive lifters, and others who predominantly train with methods that stress this joint, to use assistance equipment, such as knee wraps, braces, and knee sleeves. ...
... Knee wraps have historically been credited in powerlifting as a method to increase lifted loads (9). In addition, previous work has examined the effects of knee wraps with varying materials on several performance indices, such as muscular power and strength (7). ...
... Wrap type, wrapping technique, angles of flexion, and wrap tightness can all affect the level of assistance provided to the wearer (7). Ostensibly, wraps are believed to enact through various mechanisms, including increased mechanical assistance, enhancement of blood flow and associated knee joint pliability through tissue warming, an improved kinesthetic (proprioceptive) awareness, and augmented psychologically based confidence (9). Conversely, little research exists on neoprene knee sleeve use for performance (7). ...
Neoprene knee sleeves are commonly employed by powerlifters and recreational users, but are heavily under-researched. Furthermore, no data exist on whether knee sleeves of varying compressive tightness impact muscular performance similar to commonly used knee wraps, which are both generally effective and more so when increasingly constrictive. Fifteen resistance trained, knee sleeve-naïve, recreational weight lifting males (22.1±4.1y; 177.5±5.9cm; 87.8±7.8kg) visited the laboratory on three separate occasions one week apart, assigned in a randomized, crossover, and counterbalanced fashion to either a minimally-supportive control condition knee sleeve (CS), manufacturer-recommended sizing neoprene knee sleeve (NS), or a one-size smaller (than NS) neoprene knee sleeve (TS). On each visit, subjects sequentially completed vertical jump (countermovement and squat jumps for both peak and mean power), one-repetition maximum (1RM) barbell squat and GymAware assessments (peak power, peak velocity, and dip) at 90% (reported) and 100% (tested) 1RM, as well as one-leg extension (1RM, repetitions to failure and total volume-load at 75%1RM) tests. All data was analyzed via one-way repeated measures ANOVA at p<.05. Analysis revealed a significant condition effect on barbell squat 1RM (p=.003; η2=.339) , whereby both NS (p=.044; 166±24kg) and TS (p=.019; 166±21kg) outperformed CS
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(161±22kg), with no difference between neoprene sleeves. Conversely, no other tested parameters differed between knee sleeve conditions (p > .05). The present results demonstrate that neoprene knee sleeves may function independent of tightness, relative to recommended sizing and ultimately unlike knee wraps. Furthermore, the singular benefits observed on barbell squat maximal strength potentially suggests an exercise-specific benefit yet to be fully elucidated.
... This suggests that the effectiveness of external compression may be mainly conditioned by the width of the cuff. Furthermore, as suggested by Wilk et al. [14], increased performance during exercise with external compression may also be associated with the mechanical energy generated by the cuff [33]. A cuff is a passive element, but during the eccentric phase of the movement it can produce additional elastic energy, which is returned during the concentric phase of the movement [14,33]. ...
... Furthermore, as suggested by Wilk et al. [14], increased performance during exercise with external compression may also be associated with the mechanical energy generated by the cuff [33]. A cuff is a passive element, but during the eccentric phase of the movement it can produce additional elastic energy, which is returned during the concentric phase of the movement [14,33]. Therefore, not only physiological factors but also mechanical energy generated by the cuff can be a potential factor that influences the magnitude of acute changes during exercise under external compression. ...
... One of the most common and effective exercises for lower limb hypertrophy, strength, and power development is the back squat (SQ). The SQ is often a basic exercise in resistance training programs as well as a powerlifting competition [33][34][35][36][37]. Although the SQ is considered a highly effective exercise for developing the power output of the lower limbs [35,38], no studies have assessed the impact of external compression with BFR on acute changes during the SQ. ...
The aim of the present study was to evaluate the effects of external compression with blood flow restriction on power output and bar velocity changes during the back-squat exercise (SQ). The study included 10 judo athletes (age = 28.4 ± 5.8 years; body mass = 81.3 ± 13.1 kg; SQ one-repetition maximum (1-RM) 152 ± 34 kg; training experience 10.7 ± 2.3 years).
Methods:
The experiment was performed following a randomized crossover design, where each participant performed three different exercise protocols: (1) control, without external compression (CONT); (2) intermittent external compression with pressure of 100% arterial occlusion pressure (AOP) (EC-100); and (3) intermittent external compression with pressure of 150% AOP (EC-150). To assess the differences between conditions, the participants performed 3 sets of 3 repetitions of the SQ at 70% 1-RM. The differences in peak power output (PP), mean power output (MP), peak bar velocity (PV), and mean bar velocity (MV) between the three conditions were examined using repeated measures two-way ANOVA.
Results:
The post hoc analysis for the main effect of conditions showed a significant increase in PP (p = 0.03), PV (p = 0.02), MP (p = 0.04), and MV (p = 0.03), for the EC-150, compared to the CONT. Furthermore, a statistically significant increase in PP (p = 0.04), PV (p = 0.03), MP (p = 0.02), and MV (p = 0.01) were observed for the EC-150 compared to EC-100. There were no significant changes in PP, PV, MP, and MV, between EC-100 and CONT conditions.
Conclusion:
The results indicate that the use of extremely high-pressure external compression (150% AOP) during high-loaded (70% 1-RM) lower limb resistance exercise elicits an acute increase in power output and bar velocity.
... The use of elastic knee wraps when squatting, has also been shown to provide direct mechanical assistance to the BBS (Harman & Frykman, 1990;Lake, Carden, & Shorter, 2012;Totten, 1990). This manifests as an increased Fv, and as such elastic knee wraps are banned from non-equipped powerlifting and Olympic weightlifting (although knee sleeves that supposedly provide less elastic assistance are allowed) (Totten, 1990). ...
... In powerlifting and Olympic weightlifting, it is common for athletes to employ a variety of external material aids such as weightlifting/squat shoes/boots (International Weightlifting Federation, 2015;Sato, Fortenbaugh, & Hydock, 2012;Sato, Fortenbaugh, Hydock, & Heise, 2013), thick belts (Aurslanian, 1993;Bourne & Reilly, 1991;Faigenbaum & Liatsos, 1994;Harman, Rosenstein, Frykman, & Nigro, 1989;Kingma et al., 1976;Lander, Hundley, & Simonton, 1992;Lander, Simonton, & Giacobbe, 1990;McGill, Norman, & Sharratt, 1990;Miyamoto, Iinuma, Maeda, Wada, & Shimizu, 1999;Renfro & Ebben, 2006;Zink, Whiting, Vincent, & McLaine, 2001), and elastic knee wraps (Harman & Frykman, 1990;Totten, 1990) that may influence muscular activity throughout a BBS. When performing a BBS in standard running shoes, Sinclair, McCarthy, Bentley, Hurst, and Atkins (2014) reported a significantly greater activation in the rectus femoris compared to a barefoot condition, and no significant difference in activity was reported when weightlifting shoes were worn. ...
... respectively (Gomes et al., 2015). However, elastic knee wraps in particular, not knee sleeves (which supposedly provide elastic assistance) have been shown to provide direct mechanical assistance to lifters (Harman & Frykman, 1990;Lake, Carden, & Shorter, 2012;Totten, 1990), and as such are banned from non-equipped powerlifting and Olympic weightlifting (Totten, 1990). ...
The barbell back-squat is one of the most common exercises in strength and conditioning practice; especially in Olympic weightlifting and powerlifting. There are two main bar placements within the back-squat; the high-bar and low-bar positions. The high-bar position, favoured by Olympic weightlifters, closely resembles the upright body position of the two competition lifts of the sport; the snatch and clean and jerk. The low-bar position, favoured by powerlifters, typically allows greater loads to be lifted by utilising the posterior-chain musculature during the back-squat (one of the three competition lifts in the sport). Unfortunately, little research exists comparing the high-bar back-squat with the low-bar back-squat, and no research has examined either lift above 90% of one repetition maximum. Furthermore, no authors have biomechanically compared the high-bar back-squat to the Olympic lifts (e.g. snatch and clean and jerk). The aims of this thesis were to (1) review the current literature and quantitatively assess the kinetic and kinematic findings among the limited research; (2) compare and contrast the high-bar back-squat and low-bar back-squat up to maximal effort; and (3) assess the differences and/or similarities between the high-bar back-squat and the Olympic lifts. Through an extensive literature review, the high-bar back-squat was found to commonly present a larger hip angle, smaller knee angle and equivalent ankle angle compared to the low-bar back-squat; inferring the high-bar placement creates a more upright truck position for the lifter and requires more quadriceps muscle activation. Experimentally, these findings were confirmed with the high-bar back-squat producing larger hip angles and smaller knee angles compared to the powerlifters (16–21% larger and 10–12% smaller, respectively) and low-bar controls (16–21% larger and 10–12% smaller, respectively). While the Olympic weightlifters and powerlifters lifted similar relative loads, the low-bar controls were able to lift 2.5–5.2% larger relative loads compared to the high-bar controls. As expected, the high-bar back-squat also showed similar kinematics to the snatch and the clean but substantially different kinetics across all loads lifted. Performing a back-squat with a low-bar placement, situates the lifter (advanced and recreational) in a stronger position to lift larger loads compared to the high-bar placement. The establishment of a more advantageous kinematic posture during the low-bar back-squat could potentially maximise the utilisation of the stronger posterior hip musculature thus increasing the stability and moment arm at the hip. The low-bar back-squat therefore appears to provide the best chance of lifting the largest relative load. The kinematic similarities in posture between the high-bar back-squat and the Olympic lifts suggests the potential of similar trunk, hip and thigh muscular activity of key stabilising muscles and repetitive positional alignment in the “catch” position. The differing kinetics however, are more likely due to technical differences between the high-bar back-squat, snatch and clean; wherein the Olympic lifts require additional elements of upper-body strength and stability. The high-bar back-squat does appear to yield an efficient carryover to the Olympic lifts as a suitable supplementary exercise; provided the technical components of the lifts are maintained.
... The knee wrap is an equipment commonly used by weightlifters, powerlifters and recreational resistance training subjects aiming to stabilize the knee, to improve the strength performance (gain mechanical advantage) or to improve the confidence during back squat exercises [1,2]. The knee wrap is a long wrap of elastic material (tick canvas interwoven with rubber filaments) with approximately 2 meter long, which is wrapped around the knees as tight as possible [3,4]. In general, when the knee is flexed against an external resistance during a squat exercise, the elastic material is stretched during the lowering phase, returning this energy during the lifting phase. ...
... This potential energy accumulated is transferred to the lifter and added to the strength performance of the movement in the concentric phase [1], and this additional effect on the strength performance is also known as carry-over effect. Only Three studies have reported the amount of carry-over of 19.8% in elite powerlifters [5], 25,1% in trained-men [3], respectively, during dynamic squat exercise. However, only one study [6] reported the carry-over of 21-22% in trained-men during isometric back squat at 90 degrees of knee flexion. ...
... Probably, the knee wrap positioning on the knee joint did not affect the maxima force during isometric contractions in trained-subjects. Additionally, there were differences between without knee wraps and both knee wrap techniques, corroborating the findings of Harman and Frykman [3] and Gomes et al., [6], though this study showed lower values of carry-over (10-13%). ...
The aim of this study was to investigate the acute effects on maximal isometric force with two different techniques of knee wraps placement (spiral and X) during back squat exercise. Twenty-one physical active participants were evaluated during this study. The back squat exercise position was set up individually, guaranteeing their thigh parallel to the floor, the arms crossed on the chest, and the feet were kept always in the same position for all trials and conditions. All subjects performed three maximal isometric back squat contractions in 4 different conditions: without knee wrap (WKW), with spiral knee wrap technique (SKW), with X knee wrap technique (XKW) and tensor (T). The peak force was acquired at a 100Hz sampling frequency, during 3 seconds, 5 minutes of resting and all conditions were randomized. The Rating of Perceived Exertion (RPE) was evaluated after each trial and condition. The results shows significant differences for peak force between conditions SKW vs WKW (P=0.044, ES=0.55, Δ%=10.8%), and XKW vs WKW (P=0.009, ES=0.62, Δ%=13.6%). The use of different knee wrap techniques (spiral and X techniques) presented an effective carry-over effect, but without differences between techniques, and the RPE was similar in all conditions.
... The knee wrap is an equipment commonly used by weightlifters and powerlifters aiming to stabilize the knee, to improve the strength performance (gain mechanical advantage) or to improve the confidence during squat exercises [1,2]. The knee wrap is a long wrap of elastic material (tick canvas interwoven with rubber filaments) with approximately 2 meter long, which is wrapped around the knees as tight as possible [3,4]. There are some studies that investigated both kinematics and kinetics of the squat exercise using the knee wrap in powerlifters [5,6] and trained subjects [4], however little has been known about its effects of loading capacity. ...
... This potenctial energy accumulated is transferred to the lifter and added to the strength performance of the movement in the concentric phase [1], and this additional effect on the strength performance is also known as carry-over. Only two studies reported the amount of carry-over of 19.8% in elite powerlifters [6] and 25,1% in subjects trained [3], respectively, during squat exercise. However, little is known about the effects of different models (stiffness) of knee wrap in the peak force during the squat exercise and how much carry-over can actually be related to the knee wrap instead of the stretch-shortening cycle. ...
... The aim of this study was to compare the effect by using different models of knee wrap (hard and soft) in peak force of trained subjects while performing a maximum voluntary isometric contraction (MVIC) in the squat exercise. There were differences between the conditions HKW and WKW (P <0.029) and between conditions WKW x SKW (P <0.038), resulting in a carry-over of 22% (ES = 1.27) and 21% (ES = 1.20) respectively, corroborating the findings of Harman and Frykman [3]. ...
The aim of this study was to investigate the acute effects on maximal isometric force without and with two kinds of knee wraps (hard and soft) during squat exercise. Ten physical active participants were evaluated during this study. All subjects were familiarized with the isometric squat position in all conditions: without and with knee wrap (hard and soft stiffness). The squat exercise position was set up individually, guaranteeing their thigh parallel to the floor, the arms crossed on the chest, and the feet were kept always in the same position for all trials and conditions. All subjects performed three maximal isometric squat contractions in 3 different conditions: without knee wrap (WKW), with soft knee wrap (SKW) and with hard knee wrap (HKW). The peak of force was acquired at a 100Hz sampling frequency, during 3 seconds, 5 minutes of resting and all conditions were randomized. The results shows significant differences for peak force between conditions WKW and HKW (P=0.029, ES=1.27, Δ%=22%]) and WKW and SKW (P=0.038, ES=1.20, Δ%=21%]). The use of the knee wrap under the presented conditions seem to increase the maximal isometric force during the squat exercise, independent of the level of stiffness of the knee wrap.
... B ack squat exercise is often used to develop and test maximal lower-body strength and forms the basis of many strength and conditioning programs and powerlifting competition (2,3). Because relatively heavy loads can be used during back squat exercise, support equipment is often worn (3,7). ...
... B ack squat exercise is often used to develop and test maximal lower-body strength and forms the basis of many strength and conditioning programs and powerlifting competition (2,3). Because relatively heavy loads can be used during back squat exercise, support equipment is often worn (3,7). Knee wraps are worn to both support the knee joint and gain mechanical advantage during back squat exercise, with anecdotal evidence suggesting that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load (3)(4)(5)(6)(7). ...
... Because relatively heavy loads can be used during back squat exercise, support equipment is often worn (3,7). Knee wraps are worn to both support the knee joint and gain mechanical advantage during back squat exercise, with anecdotal evidence suggesting that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load (3)(4)(5)(6)(7). It is thought that this is because elastic energy is generated as knee wraps stretch during the lowering phase, returning this energy during the lifting phase (3,7). ...
Lake, JP, Carden, PJC, and Shorter, KA. Wearing knee wraps affects mechanical output and performance characteristics of back squat exercise. J Strength Cond Res 26(10): 2844-2849, 2012-The aim of this study was to investigate the effects of wearing knee wraps on mechanical output and performance characteristics of back squat exercise. Ten resistance trained men (back squat 1 repetition maximum [1RM]: 160.5 ± 18.4 kg) performed 6 single back squats with 80% 1RM, 3 wearing knee wraps, 3 without. Mechanical output was obtained from ground reaction force, performance characteristics from digitized motion footage obtained from a single high-speed digital camera. Wearing knee wraps led to a 39% reduction (0.09 compared with 0.11 m, p = 0.037) in horizontal barbell displacement that continued during the lifting phase. Lowering phase vertical impulse remained within 1% across conditions; however, the lowering phase was performed 45% faster (1.13 compared with 1.57 seconds). This demonstrated that vertical force applied to the center of mass during the lowering phase was considerably larger and was likely a consequence of the generation and storage of elastic energy within the knee wrap. Subsequent vertical impulse applied to the center of mass was 10% greater (192 compared with 169 N·s, p = 0.018). Mechanical work involved in vertically displacing the center of mass was performed 20% faster and was reflected by a 10% increase in peak power (2,121 compared with 1,841 W, p = 0.019). The elastic properties of knee wraps increased mechanical output but altered back squat technique in a way that is likely to alter the musculature targeted by the exercise and possibly compromise the integrity of the knee joint. Knee wraps should not be worn during the strength and condition process, and perceived weakness in the knee joint should be assessed and treated.
... Power lifters have used compression suits for years. Benefits exist from the use of tightly bound wraps around the joints, such as the knees, as this potentially enhances force production (Harman and Frykman, 1990 ...
... Compression therapy has progressed from compartment syndrome (Matsen Limb compression has been suggested to help with anaerobic performance (Harman & Frykman, 1990 1984)(Appendix 17). All subjects completed all conditions and all trials. ...
... The compression garment chosen for this study was the LZR Jammer by Speedo. The length of the Jammer was chosen to control the amount of suit covering any joint (Harman & Frykman, 1990). By not covering multiple joints, the LZR Jammer allowed the experiment to eliminate the potential for "torque generation." ...
PURPOSE: The purpose of this study was to identify potential differences in impulse force generated during the vertical jump while wearing commercially available compression shorts as compared to non-compressive, loose fitting gym shorts.
HYPOTHESIS: Leg muscle compression will produce no significant difference in muscle performance variables generated during a standard vertical jump test when compared to no compression.
METHODS: Twenty five physically active males between the ages of 18 and 30 were recruited for this study. Each subject was asked to wear 4 types of shorts: non-compressive gym shorts (representing a control), regular fitting compression shorts (by manufacturer standard), undersized compression shorts (one size smaller than manufacturer standard), and oversized compression shorts (one size larger than manufacturer standard). The subjects were familiarized with the testing procedures and then completed the three randomized conditions on the same day. The performance tests consisted of 3 sets of 10 countermovement vertical jumps performed upon a force platform. The dependent measures included: velocity at takeoff (Vto; m·s), fatigability across jumps (Vf ; m·s) and surface electromyography (EMG; volts).The maximal impulse generated was taken from the highest curve out 4 of the 10 jumps and average power was determined across the 10 jumps in each condition. The individual compression values were then determined in each condition for each subject with the use of a custom made compression quantification device. Results: There were no significant differences (P>.05) in Vto, Vf, and EMG across compression levels. Conclusions: The compression garments produce no significant change in the forces generated during the vertical jump. Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Sciences in the School of Heath, Physical Education, and Recreation, Department of Kinesiology, Indiana University
... 28 Therefore, if these factors are not the main cause of the increase on MPV, a possible contributor could be the joint stability and sense of comfort provided by the external compression of the occlusive cuff. 15 This effect may be intensified with increased cuff pressure. 45 Several studies have suggested that flossing bands (which may have a similar stabilizing effect to inflatable cuff) may increase jump performance. ...
... 45 Several studies have suggested that flossing bands (which may have a similar stabilizing effect to inflatable cuff) may increase jump performance. 8,10,15 In this sense, one of the most recent meta-analyses that has emerged on this subject concluded that these compressive bands could have a positive impact on power and jump performance. 29 This argument could be reinforced by the results of our study, given that SQ is a more unstable exercise overall than BP. ...
Background: The aim of this study was to determine the influence of different percentages of blood flow restriction (BFR) and loads on mean propulsive velocity (MPV) and subjective perceived exertion during squat (SQ) and bench press (BP) exercises.
Hypothesis: Higher percentages of BFR will positively affect dependent variables, increasing MPV and reducing perceived exertion.
Study Design: Cross-sectional study.
Level of Evidence: Level 3.
Methods: Eight healthy young male athletes took part. Two sets of 6 repetitions at 70% 1-repetition maximum (1RM), 2 sets of 4 repetitions at 80% 1RM, and 2 sets of 2 repetitions at 90% 1RM were performed randomly; 5-minute recoveries were applied in all sets. The varying arterial occlusion pressure (AOP) applied randomly was 0% (Control [CON]), 80%, and 100%.
Results: No statistically significant differences in MPV were found during the BP exercise at any percentage of BFR at any percentage 1RM. During the SQ exercise, MPV results showed statistically significant increases of 5.46% (P = 0.04; ηp2 = 0.31) between CON and 100% AOP at 90% 1RM. The perceived exertion results for the BP exercise showed statistically significant reductions of -8.66% (P < 0.01; ηp2 = 0.06) between CON and 100% AOP at 90% 1RM. During the SQ exercise, the perceived exertion results showed significant reductions of -10.04% (P = 0.04; ηp2 = 0.40) between CON and 100% AOP at 80% 1RM; -5.47% (P = 0.02; ηp2 = 0.48) between CON and 80% AOP at 90% 1RM; and -11.83% (P < 0.01; ηp2 = 0.66) between CON and 100% AOP at 90% 1RM.
Conclusion: BFR percentages ~100% AOP at 90% 1RM improved acutely MPV (only in SQ exercises) and reduced acutely perceived exertion (in both exercises). These findings are important to consider when prescribing resistance training for healthy male athletes.
... Unfortunately, there is no discrimination in this study between equipped categories that allow for standard singlets, singleply and multi-ply squat suits, so there is no guarantee that the heavier weights lifted are because of knee wraps alone. Other studies evaluating the influence of knee wraps on the squat biomechanics (Eitner, LeFavi, & Riemann, 2011;Gomes, et al., 2014;Harman & Frykman, 1990;Lake, Carden, & Shorter, 2012;Sinclair, et al., 2020) do not focus on one rep max performance, and hence the findings are inconclusive. Some interesting information is declared, such as the drawbacks of using wraps in training. ...
... From the available literature (Bennett, et al., 2021;Eitner, et al., 2011;Gomes, et al., 2014;Harman & Frykman, 1990;Herrington, et al., 2005;Lake, et al., 2012;Machek, Cardaci, et al., 2021;Sinclair, et al., 2020) conclusions are drawn through experimental procedures conducted on a small number of participants. With the exception of Eitner et al. (2011), the participants in these studies carry out resistance training for purely recreational purposes and do not lift competitively. ...
The aim of the study was to evaluate the efficacy of knee wraps for competitive powerlifters. To achieve this, an analysis of powerlifting results dating back to 1964 has been conducted. From these results the one repetition max (1RM) squat was evaluated, specifically examining the influence of competitors using knee wraps versus raw (allowing only neoprene knee sleeves). Student’s t-test was used to compare the 1RM squat for male raw competitors (n=270,268) to those using wraps (n=26,576); and likewise for female raw (n=136,530) versus wraps (n=11,468). Overall, the males using wraps yielded significantly higher (p<.05) 1RM squat values (203 kg ± 46.8) than their raw counterparts (195 kg ± 45.7). The females yielded modest, but significantly higher (p<.05) 1RM squat values for raw (112 kg ± 29.3), compared to wraps (111 kg ± 29.8). The results were stratified by weight classes, and it was found that males in heavier classes (105, 120, and 120+ kg) significantly benefited (p<.05) from using knee wraps (+1.3, +4.8, and +6.9 kg respectively). For the lighter weight classes (59, 66, and 74 kg) knee wraps appeared significantly detrimental (p<.05) to the 1RM squat (-8.4, -4.4, and -3.6 kg), respectively. Only the heaviest female weight class (84 kg+) saw a significant benefit (p<.05) in the use of wraps with a net gain in 1RM squat of 4.5 kg. Again, wraps were shown to be significantly detrimental (p<.05) to the lighter weight classes (47, 52, 57, and 63 kg) with a net loss in 1RM squat (-3, -5.3, -3.6, and -3.3 kg), respectively. Considering these findings, it is suggested that only males in the heaviest three weight classes (105, 120, and 120+ kg), as well as females in the heaviest weight class (84+ kg), stand to gain any benefit from the use of knee wraps in competition.
... Secondo quanto appreso dalla letteratura in materia, indossare una ginocchiera consente agli atleti di sollevare carichi maggiori e di eseguire un maggior numero di ripetizioni. 35 Il bracciale è un elemento passivo, tuttavia, durante l'esercizio fisico e in special modo durante la fase eccentrica della contrazione, l'allungamento del materiale di cui è costituito potrebbe fornire ulteriore flessibilità. L'energia rilasciata dal bracciale durante le contrazioni concentriche può influenzare i risultati relativi all'output di potenza e alla velocità espressi durante l'esercizio. ...
... It has been reported that wearing a knee brace allows athletes to lift greater loads and perform more repetitions. 35 The cuff is a passive element; however, during exercise, particularly during the eccentric phase, extension of the cuff material could provide additional flexibility. The energy released from the cuff during concentric contractions can affect the power outcomes and velocity during exercise. ...
BACKGROUND: This study aimed to analyze the effects of different arterial occlusion pressure (AOP) percentages of blood flow restriction (BFR) training combined with squat exercise (SQ) on acute exercise.
METHODS: Seventeen male volunteers (24.94±5.64 years) were included in the study. Participants underwent adaptation sessions and a one-repetition maximum (1-RM) test. Participants were randomly assigned to three groups: resistance training (RT) only without blood flow restriction (BFR 0%) and two different AOP groups with BFR (80% and 150%) applied to the lower limb; the groups were termed BFR0, BFR80, and BFR150, respectively. SQ was applied as a back semi-squat in all exercise sets. The acute effects of the exercise on strength and endurance performance were evaluated by repetition number, mean and peak power, mean and peak velocity, and rate of perceived exertion (REP).
RESULTS: BFR0-150 had the highest scores in terms of repetition number, mean power, mean velocity, and REP among all three groups (P≤0.05). The number of repetitions, mean power, and mean velocity were significantly higher in the BFR80 and BFR150 groups than in the BFR0 group (P<0.05). However, REP was significantly lower in BFR80 compared to the BFR150 and BFR0 groups (P<0.05).
CONCLUSIONS: Performing back squat all-out exercise with BFR150 resulted in the best acute exercise effects. This suggests that BFR training can provide trainers and athletes with more benefits in performing sports programs in terms of the number of repetitions with the same loads and power outputs as traditional strength training.
KEY WORDS: Muscle strength; Resistance training; Ischemia
... Secondo quanto appreso dalla letteratura in materia, indossare una ginocchiera consente agli atleti di sollevare carichi maggiori e di eseguire un maggior numero di ripetizioni. 35 Il bracciale è un elemento passivo, tuttavia, durante l'esercizio fisico e in special modo durante la fase eccentrica della contrazione, l'allungamento del materiale di cui è costituito potrebbe fornire ulteriore flessibilità. L'energia rilasciata dal bracciale durante le contrazioni concentriche può influenzare i risultati relativi all'output di potenza e alla velocità espressi durante l'esercizio. ...
... It has been reported that wearing a knee brace allows athletes to lift greater loads and perform more repetitions. 35 The cuff is a passive element; however, during exercise, particularly during the eccentric phase, extension of the cuff material could provide additional flexibility. The energy released from the cuff during concentric contractions can affect the power outcomes and velocity during exercise. ...
... point of view it seems the highest benefit comes from the application of knee wraps and the suit, however there is no data analyzing the independent impact of knee wrap's, suit or the erector shirt on maximal lifted load. Research by Harman and Frykman[16], confirmed that wearing knee wraps allows athletes to lift greater loads or perform more repetitions during a set. The phenomena of supportive gear can be explained by the elastic energy generated by the knee wraps stretch during the lowering phase, and then returning the mechanical energy during the lifting phase[16]. ...
... Research by Harman and Frykman[16], confirmed that wearing knee wraps allows athletes to lift greater loads or perform more repetitions during a set. The phenomena of supportive gear can be explained by the elastic energy generated by the knee wraps stretch during the lowering phase, and then returning the mechanical energy during the lifting phase[16]. The suit has a similar mechanism, however, it concerns the hip area and the spine extensor area. ...
The competition in powerlifting has been divided into two divisions, with gear equipment (EQ)
and without gear equipment (RAW). When competing in the EQ division, additional supportive gear can be
worn by the athletes, while in the RAW division such gear is not allowed. The aim of the study was to compare
the results of the RAW and EQ powerlifting divisions based on the results of world championships and current
world records. One-hundred and twenty powerlifters (63 men, 57 women) were included to the analysis. Post
hoc analysis for the results of men’s world championships indicated significantly higher results of the barbell
squat (SQ; p < 0.001; ES = 1.31), bench press (BP; p < 0.001; ES = 1.27) and deadlift (DL; p < 0.001;
ES = 0.37) for EQ compared to the RAW division. Post hoc analysis for the results of women’s world championships
indicated significantly higher results of the SQ (p < 0.001; ES = 1.31), BP (p < 0.001; ES = 1.13) and DL
(p < 0.001; ES = 0.71) for the EQ compared to the RAW division. Post hoc analysis for men’s world record
indicated significantly higher results in the SQ (p < 0.001; ES = 1.32) and BP (p < 0.001; ES = 1.24) for the
EQ compared to the RAW division. Furthermore, there were no significant differences in the results of world
records in the DL (p = 0.901; ES = 0.26) between the EQ and RAW divisions. Post hoc analysis for women’s
world records indicated significantly higher results in the SQ (p < 0.001; ES = 1.22) and BP (p < 0.001;
ES = 1.99) for the EQ compared to RAW division. The main finding of the study was that supportive gear
increases maximal load lifted during powerlifting competition.
... The most likely factor that may have enhanced PV in the present study in both BFR conditions is the mechanical energy generated by the cuff (Rawska et al., 2019;Wilk et al., 2020d,f). A cuff is a passive element, but during the eccentric phase of the movement, the strain of the material of the cuff, can store and return elastic energy during the concentric phase of the movement (Harman and Frykman, 1990;Wilk et al., 2020f). This effect may be similar with the phenomenon of enhanced mechanical energy when compressive gear (special shirt for example Inzer or Titan) is used during bench press or powerlifting competitions (Harman and Frykman, 1990), where the energy stored in these elements during the eccentric phase is returned during the lifting phase, resulting in a "rebound" effect. ...
... A cuff is a passive element, but during the eccentric phase of the movement, the strain of the material of the cuff, can store and return elastic energy during the concentric phase of the movement (Harman and Frykman, 1990;Wilk et al., 2020f). This effect may be similar with the phenomenon of enhanced mechanical energy when compressive gear (special shirt for example Inzer or Titan) is used during bench press or powerlifting competitions (Harman and Frykman, 1990), where the energy stored in these elements during the eccentric phase is returned during the lifting phase, resulting in a "rebound" effect. This may be a possible explanation for the increases in PV, but not MV, during fast movements against lower resistive loads. ...
This study evaluated the effects of continuous and intermittent blood flow restriction (BFR) with 70% of full arterial occlusion pressure on bar velocity during the bench press exercise against a wide range of resistive loads. Eleven strength-trained males (age: 23.5 ± 1.4 years; resistance training experience: 2.8 ± 0.8 years, maximal bench press strength – 1RM = 101.8 ± 13.9 kg; body mass = 79.8 ± 10.4 kg), performed three different testing protocols in random and counterbalanced order: without BFR (NO-BFR); intermittent BFR (I-BFR) and continuous BFR (C-BFR). During each experimental session, subjects performed eight sets of two repetitions each, with increasing loads from 20 to 90% 1RM (10% steps), and 3 min rest between each set. In the C-BFR condition occlusion was kept throughout the trial, while in the I-BFR, occlusion was released during each 3 min rest interval. Peak bar velocity (PV) during the bench press exercise was higher by 12–17% in both I-BFR and C-BFR compared with NO-BFR only at the loads of 20, 30, 40, and 50% 1RM (p < 0.001), while performance at higher loads remained unchanged. Mean bar velocity (MV) was unaffected by occlusion (p = 0.342). These results indicate that BFR during bench press exercise increases PV and this may be used as an enhanced stimulus during explosive resistance training. At higher workloads, bench press performance was not negatively affected by BFR, indicating that the benefits of exercise under occlusion can be obtained while explosive performance is not impaired.
... Likewise, in case of the analysis of the 1RM test results, the mechanical compression and related work generated by the cuff is a potential cause and explanation of the obtained increase in TUT and REP for the BFR 150 condition. Research by Harman and Frykman (1990) confirmed that wearing knee wraps allows athletes to lift greater loads or perform more repetitions during a particular set. This phenomenon can be explained by the elastic energy generated as the knee wraps stretch during the lowering phase, and then returning the mechanical energy during the lifting phase (Harman and Frykman, 1990). ...
... Research by Harman and Frykman (1990) confirmed that wearing knee wraps allows athletes to lift greater loads or perform more repetitions during a particular set. This phenomenon can be explained by the elastic energy generated as the knee wraps stretch during the lowering phase, and then returning the mechanical energy during the lifting phase (Harman and Frykman, 1990). A similar effect may apply to the occlusion cuffs. ...
The main goal of the present study was to evaluate the acute effects external compression with blood flow restriction (BFR) at 100 and 150% of full arterial occlusion pressure (AOP) on maximal strength and strength-endurance performance during the bench press (BP) exercise. The study included 12 strength-trained male subjects (age = 23.2 ± 2.66 years; body mass = 75.3 ± 6.33 kg; height = 179.1 ± 3.82 cm), experienced in resistance training (5.7 ± 2.93 years). During the experimental sessions in a randomized crossover design, the subjects performed a 1 repetition maximum (1RM) test and three sets of the BP using 60% 1RM to failure with three different conditions: without BFR (NO-BFR); BFR with a pressure of 100% AOP (BFR100); and BFR with a pressure of 150% AOP (BFR150). The differences between the NO-BFR, BFR100, and BFR150 conditions were examined using repeated measures ANOVA. The ANOVA indicated significant main effect for condition in 1RM, number of performed repetitions (REP), and time under tension (TUT) (p < 0.01). Post hoc analyses for the main effect indicated significant increases in 1RM (p < 0.01; 95.00 ± 15.37 vs 91.87 ± 15.99), REP (p < 0.01; 17.56 ± 3.36 vs 15.67 ± 5.24), and TUT (p < 0.01; 32.89 ± 6.40 vs 28.72 ± 6.18) for the BFR150 condition compared to NO-BFR. Furthermore, significant increases in REP (p = 0.03; 17.56 ± 3.36 vs 16.47 ± 4.01) and TUT (p = 0.03; 32.89 ± 6.40 vs 30.00 ± 6.45) were observed for the BFR150 condition compared to the BFR100. The results of the present study indicate that high external compression increases maximal strength evaluated by the 1RM test, as well as endurance performance during three sets of the BP exercise.
... Thus, mechanical energy accumulated and generated by the cuff can be a potential cause and explanation of the obtained results. Previous research has confirmed that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load (13). It is believed that this is because elastic energy is generated as knee wraps stretch during the lowering phase, returning the mechanical energy during the lifting phase (13). ...
... Previous research has confirmed that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load (13). It is believed that this is because elastic energy is generated as knee wraps stretch during the lowering phase, returning the mechanical energy during the lifting phase (13). A similar effect may apply to the cuffs used during BFR. ...
Wilk, M, Krzysztofik, M, Filip, A, Zajac, A, Bogdanis, GC, and Lockie, RG. Short-term blood flow restriction increases power output and bar velocity during the bench press. J Strength Cond Res XX(X): 000–000, 2020—This study examined the effect of blood flow restriction (BFR) with 2 different types of cuffs on peak power output (PP), mean power output (MP), peak bar velocity (PV), and mean bar velocity (MV) in the bench press exercise (BP). Fourteen healthy strength-trained male athletes (age = 27.6 ± 3.5 years; body mass = 84.1 ± 8.0 kg; height = 175.8 ± 6.7 cm; BP 1 repetition maximum [RM] = 138.6 ± 17.8 kg) performed 3 different testing protocols as follows: without BFR (NO-BFR), BFR with a narrow cuff (BFRNARROW), and BFR with a wide cuff (BFRWIDE) in a randomized crossover design. During all sessions, subjects performed one set of 3 repetitions of the BP exercise using 70% 1RM. Cuff pressure was set to approximately 90% full arterial occlusion pressure of the upper limb at rest. Analyses of variance showed an increase in PP (by 21%, p < 0.01; effect size [ES] = 1.67), MP (by 16%, p < 0.01; ES = 0.93), PV (by 22%, p < 0.01; ES = 1.79), and MV (by 21%, p < 0.01; ES = 1.36) during BFRWIDE compared with NO-BFR and a significant increase in PP (by 15%, p < 0.01; ES = 1.07), MP (by 17%, p < 0.01; ES = 0.78), PV (by 18%, p < 0.01; ES = 1.65), and MV (by 13% p < 0.01; ES = 1.00) during BFRWIDE compared with BFRNARROW. There were no significant differences in any of the variable between NO-BFR and BFRNARROW. The results of the study indicate that short-term BFR training increases power output and bar velocity during the BP exercise. However, only BFRWIDE significantly influenced bar velocity and power output, which indicates that the width of the cuff is a critical factor determining acute exercise adaptation during BFR resistance training.
... Another important factor that may have a significant effect on the higher value of REPs performed during exercise with BFR is the mechanical work generated by the tourniquet. Previous research has confirmed that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load [27,28]. It is thought that this is because elastic energy is generated as knee wraps stretch during the lowering phase, returning this energy during the lifting phase [27]. ...
... Previous research has confirmed that wearing knee wraps enables athletes to lift greater loads or perform more repetitions with a given load [27,28]. It is thought that this is because elastic energy is generated as knee wraps stretch during the lowering phase, returning this energy during the lifting phase [27]. A similar effect may occur when the cuff is used during BFR. ...
The main goal of the presented study was to assess the effect of blood flow restriction (BFR) on the maximum number of repetitions in the bench press exercise (BP) with different movement tempos. Material and methods: Four female athletes volunteered for the study. The experiment was performed following a randomized crossover design, with four different testing protocols: 2/0/X/0 fast tempo with BFR (FASTBFR); 2/0/X/0
fast tempo without BFR (FASTNO-BFR); 6/0/X/0 slow tempo with BFR (SLOWBFR) or 6/0/X/0 slow tempo without BFR (SLOWNO-BFR). During the experimental session, participants performed 5 sets of the BP at 80%1RM. The following variables were recorded: the maximal number of repetitions in every set (REPSet1-5) and the total number of repetitions performed in 5 sets (TREP). Two-way ANOVA was used to
show differences between variables. Results: There were significant differences between FASTNO-BFR and SLOWNO-BFR, between FASTBFR and SLOWBFR variables in REPSet1-5 (p < 0.05) and TREP (p < 0.01). Similarly, there were significant differences between FASTNO-BFR and FASTBFR variables in REPSet1,2,5 (p < 0.05) and TREP. Significant differences between SLOWNO-BFR and SLOWBFR variables were also found in REPSet1,5 (p < 0.05), as well as in TREP (p < 0.01). Conclusions: The use of BFR in resistance training improves the maximal number of REP during the BP.
... Wearing compression shorts improved the jump height with an increase of 6.9 mm, although subjects experienced an extra 1 BW of force during landing (Peters et al., 2009). Compressive knee wraps produced increased vertical force at the feet and thus contributed to a greater one-repetition maximum squat in competitive lifters (Harman and Frykman, 1990). ...
... However, it was noteworthy that the knee compression increased the magnitude of DR, PPF, and VJH by 19.80 %, 3.41%, and 4.87%, respectively, compared to that under the control condition. Similarly, several previous studies (Harman and Frykman 1990;Doan et al., 2003;Peters et al., 2009) showed that compressive garments and wraps improved jumping height by providing pressure around joints. ...
The purpose of this study was to determine how knee compression affected kinetic variables during vertical jumps. Ten healthy males, age 20s, performed a single maximum vertical jump and a ten-consecutive vertical jump trial without knee compression (control condition) and with knee compression. The collected data of ground reaction force were used to analyse the vertical jump height (VJH), peak active force (PAF), decay rate (DR), peak passive force (PPF), loading rate (LR), and the coefficient of variation (CV). During a maximum vertical jump, knee compression increased the magnitudes of DR, PAF, and VJH by 19.8%, 3.41%, and 4.87%, respectively, compared to those under a control condition. During ten consecutive vertical jumps, PAF and VJH showed statistically significant difference according to the repetition count. Also, the mean and CV of PAF, DR, LR, and VJH over consecutive jumps were higher in magnitude under knee compression condition than under the control condition.
... Diversos estudos investigaram os efeitos do uso da banda elástica no desempenho. [4][5][6][7][8][9] Gomes et al., 6 verificaram um aumento de 21 e 22% no pico de força durante o agachamento isométrico máximo com diferentes modelos de banda elástica (Soft e Hard, respectivamente). Marchetti et al., 9 também verificaram aumento no pico de força durante o agachamento isométrico máximo, independentemente da técnica de colocação da banda elástica (em espiral: 10,8% em "X": 13,6%). ...
... 1,8 Assim, pesar de diversos estudos evidenciarem aumento do desempenho quando a banda elástica foi utilizada, tais estudos investigaram apenas seus efeitos no complexo articular de joelho e durante a realização do exercício agachamento. 1,2,[4][5][6][7][8][9] Sendo assim, o objetivo do presente estudo foi investigar os efeitos agudos do uso da banda elástica de cotovelos no desempenho de força máxima e submáxima, no volume absoluto e percepção subjetiva de esforço/desconforto durante o exercício supino reto livre. A hipótese principal considera que o uso da banda elástica de cotovelos aumenta o desempenho máximo e submáximo do exercício supino, assim como afeta negativamente a percepção de esforço. ...
RESUMO Introdução: A banda elástica é muito utilizada por diferentes tipos de atletas e por praticantes de treina-mento de força recreacionais, no intuito de melhorar o desempenho no levantamento de cargas. Objetivo: Investigar os efeitos agudos do uso da banda elástica de cotovelos no desempenho de força, no volume absoluto e percepção subjetiva de esforço durante o exercício supino reto livre. Métodos: Na primeira visita, foi realizada a familiarização com o exercício supino reto livre com banda (CB) e sem banda (SB) elástica de cotovelos. Na segunda visita, foi realizado o teste de 1RM no exercício supino reto livre, nas condições CB e SB. Na terceira visita, foi realizado o teste de repetições máximas até a falha concêntrica (RMs) a 70% de 1RM (CB e SB). Após cada teste, os sujeitos foram questionados quanto a sua percepção subjetiva de esforço (PSE) e de desconforto (PSD). Teste t de student pareado foi utilizado para comparar os valores de 1RM e RMs, com e sem banda elástica. Para a PSD e a PSE foram utilizadas análises descritivas. Resultados: No teste de 1RM foi verificado um aumento significante para a condição CB, quando comparado à condição SB (P<0,05). No teste de RMs e cálculo do volume absoluto, foi verificado um aumento significante para a condição CB (P<0,05). A PSE não apresentou diferenças em todas as condições testadas (P>0,05). A PSD apresentou alto grau de des-conforto apenas com banda elástica em todas as condições. Conclusão: A banda elástica de cotovelos aumenta a carga levantada no teste de 1RM e o número de repetições máximas durante o exercício supino reto livre e, consequentemente, no volume absoluto. A banda elástica não altera a percepção subjetiva do esforço, mas aumenta o desconforto durante o exercício.
... Several studies have investigated the effects of using the elastic wrap in performance. [4][5][6][7][8][9] Gomes et al., 6 verified a 21 and 22% increase in peak force during maximum isometric squatting with different elastic band models (Soft e Hard, respectively). Marchetti et al., 9 also observed an increase in peak force during maximum isometric squatting, regardless of the technique of elastic wrap placement (in spiral: 10,8% in "X": 13,6%). ...
... 1,8 So, although several studies showed an increase in performance when the elastic wrap was used, such studies only investigated its effects on the knee joint complex and during the exercise of the squat exercise. 1,2,[4][5][6][7][8][9] Therefore, the objective of the present study was to investigate the acute effects of elbow wrap on maximal and submaximal strength performance, absolute volume and Rating of perceived exertion/discomfort during the bench press exercise. The main hypothesis considers that the use of elastic wrap of elbows increases the maximum and submaximal performance of the bench press exercise, as well as negatively affects the perception of effort. ...
Introduction:
The elastic wrap is widely used by different types of athletes and recreational practitioners of strength training in order to improve weightlifting performance.
Objective:
The objective was to investigate the acute effects of elbow wrap on strength performance, absolute volume, and rating of perceived exertion/discomfort during the bench press (BP) exercise.
Methods:
The experimental protocol was divided into three laboratory sessions. At the first session, a bench press familiarization phase was performed with (EW) and without (WEW) elastic elbow wrap. During the second session, the 1RM test was carried out in the bench press exercise under both EW and WEW conditions. At the third session, the repetition maximum (RM) test at 70% of 1RM (EW and WEW) was performed until concentric failure. After each session, subjects were consulted about their rate of perceived exertion (RPE), and discomfort (PSD). A paired student t-test was used to compare the values of 1RM and RMs with and without elastic wraps. Descriptive analysis was used for RPE and PSD.
Results:
For the 1RM test, there was a significant increase for the EW condition when compared to WEW (p<0.05). In the RMs test and absolute volume calculation, there was a significant increase for the EW condition (p<0.05). RPE did not differ in any of the conditions tested (p>0.05). PSD presented a high degree of discomfort with elastic wraps in all conditions.
Conclusion:
Elastic elbow wraps increase the load lifted in the 1RM test, and the maximum number of repetitions during the BP exercise, and consequently, the absolute volume. The elastic elbow wrap does not alter the subjective perception of effort, but it increases discomfort during exercise.
... 1,2 The EKW has a composite manufactured of polyester frames reinforced with elastic material and measuring two meters in length, usually wrapped around the knee as tightly as possible just before the squat be executed. 3,4 The EKW, in general, works as an ergogenic agent that through elastic deformation of the material accumulates elastic energy and gravitational potential (during the descending phase of the squat) and consequently increases its loading capacity in the ascending phase, additional force effect known as carry over. 1 Although EKW was extensively used in strength training, only three studies investigated the EKW's carry over effect on strength production, with a dynamic squatting study in powerlifters (19,8%), 5 a study with strength-trained subjects during passive squatting (25,1%) 3 and a study in subjects trained in strength during maximum isometric squatting (21-22%). 6 Additionally, Lake et al., 4 compared the effect of EKW use on kinetic and kinematic variables during squatting in subjects trained in strength. ...
... However, the carry over effect found in the present study was considerably higher than that observed in the aforementioned studies. 3,6 It is probable that EKW contributed with a greater mechanical magnitude during extension of knees in the extensor chair due to the lower external resistance involved during the task (leg and foot segments), which are equivalent to approximately 9.6 and 3.4 % of body weight, respectively. 20 While performing the maximal isometric squatting exercise, the external resistance is composed of approximately 87% of body weight 20 (trunk, upper limbs, neck and head). ...
Introduction:
The elastic knee wrap (EKW) is a device used by powerlifters, weightlifters and subjects undergoing strength training with the aim of stabilizing the knee joint and increasing the development of strength (carryover effect).
Objective:
To compare the effects of elastic knee wrap use on muscular activity of the vastus lateralis (VL) and on knee extension force during maximum voluntary isometric contraction (MVIC) on the knee extensor chair.
Methods:
The study included 18 healthy male strength trained (>1 year) subjects (age: 25.56 ± 4.84 years, total body mass: 81.83 ± 8.73 kg, height: 176 cm ± 5.17). Three five-second maximum voluntary isometric contractions (MVICs) of the knee extensors were performed with a 10-second interval between attempts, for each experimental condition: control (C), with elastic knee wrap (EKW), and with tensor (T). The performance of the knee extensors and VL muscle activity were evaluated. A repeated measures ANOVA was used to compare the dependent variables (carryover, peak force, IEMG and Impulse).
Results:
For carryover, the use of EKW presented a higher value (74.21%) than the control condition (p <0.001, d = 0.96) and was 79.37% higher than the tensor (p <0.001, d = 0.97). Peak force was 12.2% higher in condition C compared to EKW (p = .018, d = 0.71). For impulse, the control condition presented an increase of 8% compared to EKW use (p = .015, d = 0.62). No significant differences were observed for IEMG.
Conclusion:
Elastic knee wrap use increased strength production capacity during knee extension. The removal of the mechanical effect originating from carryover during MVIC reduces the strength performance of the knee extensors, but not the muscular activation of the VL. Level of Evidence I; Therapeutic studies - Investigation of treatment results.
... For the authors, this lack of improvement in maximal muscle power production may be partially related to the level of compression applied by the garment. In fact, it has already been reported that higher levels of compression applied around the knees can substantially increase the vertical force component during competitive lifts, and therefore augment maximum strength performance in the squat exercise (Harman and Frykman 1990). Actually, in this study, we opted to use comfortable compression clothing (with moderate levels of compression), since the subjects had to perform a considerable series of tests wearing these garments. ...
... Nevertheless, due to the recognized properties of compression in reducing the perception of effort and facilitating blood lactate removal (Faulkner et al. 2013), it would be interesting to test its effectiveness during repeated-sprint sets. Furthermore, it remains to be examined whether garments with extreme levels of compression can enhance top-speed performance, since it was demonstrated that very-high intensity compression may increase the vertical force component (which is directly related to higher velocities) (Harman and Frykman 1990;Nilsson and Thorstensson 1989;Weyand et al. 2000). ...
Background:
Compression garments are thought to aid performance in some selected speed-power activities owing to improved sensory feedback and proprioception. The aim of this study was to test the effects of using compression garments on speed and power-related performances in elite sprinters with visual impairment, who rely more on proprioception to perform than their Olympic peers. Eight top-level Paralympic sprinters competing in 100- and 200-m races performed, in the following order: unloaded squat jump (SJ), loaded jump squat (JS) and sprint tests over 20- and 70-m distances; using or not the compression garment. The maximum mean propulsive power value obtained during the JS attempts (starting at 40 % of their body mass, after which a load of 10 % of body mass was progressively added) was considered for data analysis purposes. The athletes executed the SJ and JS attempts without any help from their guides. Magnitude-based inference was used to analyze the results.
Findings:
The unloaded SJ was possibly higher in the compression than the placebo condition (41.19 ± 5.09 vs. 39.49 ± 5.75 cm). Performance differences in the loaded JS and sprint tests were all rated as unclear.
Conclusions:
It was concluded that the acute enhancement in vertical jump ability should be explored in the preparation of Paralympic sprinters during power-related training sessions. However, chronic effects in Paralympic athletes wearing compression garments need to be further tested, in order to support its use as a specific training aid.
... However, Verhagen et al. (2001) cautioned that restricted range of motion does not necessarily increase joint protection. For example, Harman and Frykman (1990) reported that knee wraps worn during powerlifting, back squat exercise at 80% of one-repetition maximum, actually altered the biomechanics of the movement as compared to the no knee wrap condition and increased injury potential to the knee joint and lowerbody musculature (Harman & Frykman, 1990) . ...
... However, Verhagen et al. (2001) cautioned that restricted range of motion does not necessarily increase joint protection. For example, Harman and Frykman (1990) reported that knee wraps worn during powerlifting, back squat exercise at 80% of one-repetition maximum, actually altered the biomechanics of the movement as compared to the no knee wrap condition and increased injury potential to the knee joint and lowerbody musculature (Harman & Frykman, 1990) . ...
Shot put throwing distances of 18 male Division I track and field athletes in the United States were compared among three wrist wrap conditions: 1) a large heavy wrist wrap, typically worn by athletes competing in the shot put event, 2) a small light wrist wrap and 3) no wrist wrap. The average and maximum throwing distances when the athletes were wearing the heavy wrist wrap (12.31 ± 1.699maximum; 11.92 ± 1.627average) were greater than when the athletes were not wearing a wrist wrap (12.05 ± 1.550maximum; 11.70 ± 1.457average). Performance increases exceeded criteria for the smallest worthwhile improvements in the shot put event, suggesting that heavy wrist wraps provide a competitive advantage. These results revealed previously undocumented, beneficial effects of taping and bracing on sports performance in the shot put throw.
... One study looking at compressive gear in powerlifting athletes found significantly higher maximal lifts in bench press, deadlift and squats in athletes using compressive support gear (Michal et al., 2020). It is suggested that the compressive gear such as knee wraps store elastic potential during the eccentric phase of the lift, then returning that energy as mechanical force during the concentric phase of the lift (Harman and Frykman, 1990). High BFR pressures (100-150% LOP) have been shown to significantly increase 1RM strength and repetitions to failure against controls not using external compression (Wilk et al., 2020). ...
Background
Blood flow restriction (BFR) training at lower exercise intensities has a range of applications, allowing subjects to achieve strength and hypertrophy gains matching those training at high intensity. However, there is no clear consensus on the percentage of limb occlusion pressure [%LOP, expressed as a % of the pressure required to occlude systolic blood pressure (SBP)] and percentage of one repetition max weight (%1RM) required to achieve these results. This review aims to explore what the optimal and minimal combination of LOP and 1RM is for significant results using BFR.
Method
A literature search using PubMed, Scopus, Wiley Online, Springer Link, and relevant citations from review papers was performed, and articles assessed for suitability. Original studies using BFR with a resistance training exercise intervention, who chose a set %LOP and %1RM and compared to a non-BFR control were included in this review.
Result
Twenty-one studies met the inclusion criteria. %LOP ranged from 40 to 150%. %1RM used ranged from 15 to 80%. Training at 1RM ≤20%, or ≥ 80% did not produce significant strength results compared to controls. Applying %LOP of ≤50% and ≥ 80% did not produce significant strength improvement compared to controls. This may be due to a mechanism mediated by lactate accumulation, which is facilitated by increased training volume and a moderate exercise intensity.
Conclusion
Training at a minimum of 30 %1RM with BFR is required for strength gains matching non-BFR high intensity training. Moderate intensity training (40–60%1RM) with BFR may produce results exceeding non-BFR high intensity however the literature is sparse. A %LOP of 50–80% is optimal for BFR training.
... These changes may impair training performance and increase stress on the soft tissues within joints, which may increase the risk of sustaining an injury (9). Previous work has suggested that lifters may be able to reduce the impact of some of these issues by using ergogenic aids during lifting tasks (3,8,12,27). ...
Brice, SM, Doma, K, and Spratford, W. Effect of footwear on the biomechanics of loaded back squats to volitional exhaustion in skilled lifters. J Strength Cond Res XX(X): 000-000, 2021-This study examined whether footwear influences the movement dynamics of barbell back squats to volitional exhaustion in experienced lifters. Eleven men (1 repetition maximum [1RM] = 138 ± 19 kg; 1RM % body mass = 168 ± 18%) performed 3 sets (5-12 ± 4 repetitions per set) of loaded barbell back squats to volitional exhaustion using raised-heel and flat-heel footwear. Barbell motion as well as moments, angles, angular velocity, and power in the sagittal plane at the ankle, knee, hip, and lumbopelvis were examined during the second repetition of the first set (Tsecond) and the final repetition of the third set (Tfinal). There were significant reductions (p < 0.05) in lower-limb concentric angular velocity and power output for both footwear conditions. For the raised-heel condition at Tfinal, hip and knee concentric angular velocities were significantly slower (p < 0.05), and knee concentric power output was significantly less (p < 0.05) compared with the flat-heel condition. A reduction in barbell velocity was not observed for the raised-heel condition despite there being reduction in hip and knee angular velocities. Furthermore, no differences were identified in lower-limb joint moments or any of the biomechanical characteristics of the lumbopelvis between the footwear conditions. The findings of this study suggest that neither type of footwear reduced joint loading or improved joint range-of-motion.
... Dette påverka truleg både hopphøgde i spensttesten og leddutslaget under 60 meter sprint. (Doan et al., 2003), på same måte som elastiske band surra rundt knea i vektløfting er vist å gi prestasjonseffekt som følgje av at mekaniske krefter dannar moment over leddet (Harman & Frykman, 1990 ...
... 1, 2 A BEJ possui em sua composição um compósito formado por tramas de poliéster reforçado com material elástico e medindo dois metros de comprimento, esta normalmente é envolvida ao redor do joelho o mais apertado possível imediatamente antes da execução do agachamento. 3,4 A BEJ, de forma geral, funciona como um agente ergogênico que através da deformação elástica do material acumula energia elástica e potencial gravitacional (durante a fase descendente do agachamento) e consequentemente, aumenta sua capacidade de carregamento na fase ascendente, esse efeito de força adicional é conhecido como carry over. 1 Apesar da BEJ ser extensamente utilizada no treinamento de força, apenas três estudos investigaram o efeito carry over da BEJ na produção de força, sendo um estudo com o agachamento dinâmico em powerlifters (19,8%), 5 um estudo com sujeitos treinados em força durante o agachamento passivo (25,1%) 3 e um estudo em sujeitos treinados em força durante o agachamento isométrico máximo (21-22%). 6 Adicionalmente, Lake et al., 4 ± 5,17), sexo masculino, entrenado en fuerza (> 1 año). ...
Introdução: A banda elástica de joelhos (BEJ) é um equipamento utilizado por powerlifters, weightlifters e sujeitos treinados em força, com o objetivo de estabilizar a articulação do joelho e aumentar o desempenho da força (efeito carry over). Objetivo: Comparar os efeitos do uso da banda elástica de joelhos na atividade muscular de vasto lateral (VL) e na força de extensores de joelhos, durante a contração voluntária máxima iso-métrica (CVMI) na cadeira extensora. Métodos: Participaram do estudo 18 sujeitos saudáveis (idade: 25,56 ± 4,84 anos, massa corporal total: 81,83 ± 8,73 kg, estatura: 176 ± 5,17 cm), do gênero masculino, treinados em força (> 1 ano). Foram realizadas três contrações voluntárias máximas (CVMI's de extensores de joelho, de cinco segundos por 10 segundos de intervalo entre as tentativas, para cada condição experimental: controle (C); com banda elástica de joelhos (BEJ); e com tensor (T). Foram avaliados o desempenho de extensores de joelho e a atividade muscular de VL. Uma ANOVA com medidas repetidas foi utilizada para comparar as variáveis dependentes (carry over; pico de força, IEMG e Impulso). Resultados: Para o carry over, o uso da BEJ apresentou maior valor (74,21%) quando comparada a condição controle (P<0,001, d=0,96) e 79,37% maior do que o tensor (P<0,001, d=0,97). O pico de força foi 12,2% maior na condição C comparado à BEJ (P=0,018, d=0,71). Para o impulso, a condição controle apresentou um aumento de 8% comparado ao uso da BEJ (P=0,015, d=0,62). Para a IEMG não foram observadas diferenças significantes. Conclusão: O uso da banda elástica de joelhos aumentou a capacidade de produção de força durante a extensão de joelho. A remoção do efeito mecânico proveniente do carry over, durante a CVMI, reduz o desempenho de força dos extensores de joelho, mas não a ativação muscular do VL. Nível de Evidência I; Estudos terapêuticos-Investigação dos resultados do tratamento.
... Furthermore, all results that are presented in this review are based on "un-equipped" or "raw" lifters. That is to say, those lifters that do not perform the squat with external assistance such as squat suits or elastic knee wraps (5,22,35). ...
The back-squat is a common exercise in strength and conditioning, for a variety of sports. It is widely regarded as a fundamental movement to increase and measure lower-body and trunk function, as well as an effective injury rehabilitation exercise. There are typically two different bar positions used when performing the back-squat; the traditional 'high-bar' back-squat (HBBS) and the 'low-bar' back-squat (LBBS). Different movement strategies are employed to ensure that the center-of-mass remains in the base-of-support for balance during the execution of these lifts. These movement strategies manifest as differences in 1) joint angles, 2) vertical ground reaction forces and, 3) the activity of key muscles. This review showed that the HBBS is characterized by greater knee flexion, lesser hip flexion, a more upright torso and a deeper squat. The LBBS is characterized by greater hip flexion and therefore a greater forward lean. However, there are limited differences in vertical ground reaction forces between the HBBS and LBBS. The LBBS can also be characterized by greater muscle activity of the erector spinae, adductors and gluteal muscles, whereas the HBBS can be characterized by greater quadriceps muscle activity. Practitioners seeking to develop the posterior-chain hip musculature (i.e. gluteal, hamstring and erector muscle groups) may seek to utilize the LBBS. In comparison, those seeking to replicate movements with a more upright torso, and contribution from the quadriceps may rather seek to employ the HBBS in training.
... K nee wraps (KWs) are typically worn to gain mechanical advantage during the back squat exercise, and they are also often used to increase the load lifted or the number of repetitions performed with a given load (4,9,10,13,18). In general, when the knee is flexed against an external resistance during the back squat exercise, the KW(s) elastic material is stretched during the eccentric phase and returns this energy during the concentric phase. This potential accumulated energy is transferred to the lifter and added to the strength of the movement. ...
Gomes, WA, Brown, LE, Soares, EG, da Silva, JJ, Silva, FHDdO, Serpa, ÉP, Corrêa, DA, Vilela Junior, GdB, Lopes, CR, and Marchetti, PH. Kinematic and sEMG analysis of the back squat at different intensities with and without knee wraps. J Strength Cond Res 29(9): 2482-2487, 2015-The purposes of this study were to measure the acute effects of knee wraps (KWs) on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis (VL) and gluteus maximus (GM), and rating of perceived exertion (RPE) during the back squat exercise at 2 different intensities. Fourteen resistance-trained men (age: 24 ± 4 years, height: 176 ± 6 cm, body mass: 81 ± 11 kg, back squat 1 repetition maximum [1RM]: 107 ± 30 kg, 3 ± 1 year of back squat experience) performed 1 set of 3 repetitions under 4 different conditions, to a depth of approximately 90 degrees of knee joint flexion, and in random order: KWs at 60% 1RM (KW60), KWs at 90% 1RM (KW90), without knee wraps (NWs) at 60% 1RM (NW60), and NWs at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the VL and GM, and RPE. For muscle activity, there were significant decreases in the VL NWs at 60% 1RM (p = 0.013) and a significant increase NWs at 90% 1RM (p = 0.037). There was a significant increase in VL muscle activity at 90% 1RM, when compared with 60% 1RM (KW: p = 0.001, effect size (ES) = 1.51 and NW: p < 00.001, ES = 1.67). There was a decrease in GM muscle activity NWs only at 60% 1RM (p = 0.014). There was a significant increase in GM muscle activity at 90% 1RM, when compared with 60% 1RM (KW: p < 0.001 and NW: p < 0.001). For peak hip joint flexion angle, there was significant decreases between intensities (90% 1RM < 60% 1RM) only to NWs condition (p = 0.009), and there was greater knee flexion NWs for both intensities: 60% 1RM (p < 0.001) and 90% 1RM (p = 0.018). For normalized vertical barbell displacement, there were significant differences between intensities when using KWs (p = 0.022). There were significant differences in RPE between 60 and 90% 1RM for each condition: KWs (p < 0.001) and NWs (p < 0.001). In conclusion, the use of KWs results in decreased muscle activation of the VL at the same intensity (90% 1RM).
... as have elastic sleeves [93], probably as a result of potentiated sensory feedback from skin or joint receptors. Knee wrapping commonly used by power lifters has also been effective in increasing force produced at the feet and enhance weightlifting performance [94]. The athletic performances of 6 males were compared when they wore on separate occasions a girdle then available on the market, and a prototype, results being compared with those obtained under a control condition (without a girdle). ...
Objective: Investigate whether wearing 7 mm neoprene knee sleeves during the front squat and box jump CrossFit exercises change the biomechanics of the knee joint.
Design: a cross-sectional exploratory study.
Setting: Laboratory-based.
Participants: Seventeen male healthy CrossFit participants completed front squats and box jumps with knee sleeves (KS) and without knee sleeves (WKS).
Main outcomes measures: Kinematic and kinetic data of the knee in the sagittal, frontal and transverse planes were obtained for the two tasks and under the two experimental situations. The maximum load lifted on 1 MR test was recorded under KS and WKS conditions. The GROC scales were applied after each exercise and condition to assess participants’ self-reported perception of stability.
Results: The KS reduced the knee range of motion in the transverse plane during box jump (p = 0.029) and the peak knee external adduction moment (p = 0.047) during front squat compared to WKS. The 1RM during front squat increased in KS compared to WKS (p < 0.001). Most participants (94%) reported that they felt better stability using KS and all participants (100%) believed that knee sleeves would avoid knee pain.
Conclusion: neoprene knee sleeves have little impact on the biomechanics of the knee joint during CrossFit. However, participants reported improved knee stability.
Hatfield, DL, Stranieri, AM, Vincent, LM, and Earp, JE. Effect of a neoprene knee sleeve on performance and muscle activity in men and women during high-intensity, high-volume resistance training. J Strength Cond Res XX(X): 000-000, 2021-The purpose of this study was to assess the effects of a commercially available neoprene knee sleeve (KS) on exercise performance and muscle activity during an exhaustive leg press exercise. Twenty resistance-trained individuals, 11 men {21.0 ± 2.2 years; 77.7 ± 8.7 kg; 1 repetition maximum (1RM/body mass [BM]): 0.30 ± 0.04} and 9 women (22.0 ± 3.5 years; 66.1 ± 9.1 kg; 1RM/BM: 0.30 ± 0.04), all subjects (21.5 ± 2.8 years; 72.5 ± 10.5 kg; 1RM/BM: 0.30 ± 0.04), participated in 3 testing sessions. The second and third sessions were performed using a counterbalanced and randomized design in which subjects exercised with (WS) or without (NS) KSs and performed 6 sets of leg press exercise at 80% of 1RM until failure with a 3-minute rest between sets. Number of repetitions, blood lactate (BL), heart rate (HR), rating of perceived exertion (RPE), and peak and average power were recorded after each set. Surface electromyography (EMG) of the right and left vastus lateralis muscles was also recorded to compare muscle activity between conditions. Significance was set at p ≤ 0.05, and values are presented as mean ± SD. No significant differences were observed in the total number of repetitions for all sets (p = 0.3; WS 75.3 ± 33.7, NS 79.8 ± 34.3) and the number of repetitions per set between conditions (p ≤ 0.05) or between men and women. Similarly, no significance differences (p ≤ 0.05) were observed for BL, HR, RPE, or EMG per set between conditions or between men and women. These results suggest that wearing compressive neoprene KSs has no effect on improving performance and associated variables during high-load, high-volume lower-body resistance training.
Knee wraps (KW) can be used as an ergogenic aid during the back squat to increase training volume and load. Previous investigations have examined carry‐over effect during the back squat, though the amount of torque produced at the knee due to the KWs remains unknown. Therefore, this investigation examined the influence of KWs on passive torque production, and its relationship to knee circumference. Nine resistance trained men performed two, 5s passive isometric knee extensions with (KW) and without (UW) knee wraps at nine different angles (70°,75°,80°,85°,90°,95°,100°,105°, and 110°). Data were analyzed via two‐way repeated measures ANOVA to assess differences between conditions, while Pearson Product‐Moment correlations were used to assess the relationship between torque production and knee circumference. A significant interaction was observed for passive torque, revealing differences between all angles in KW (p≤0.05), while differences during UW were only observed at angles greater than 90° (p≤0.05). Paired samples t‐tests indicated differences between conditions at every angle except 70° (p≤0.05). Knee circumference was not correlated to torque production at any angle (r = ≤ 0.411, p > 0.272). These results demonstrate the applicability of KW to passively increase torque produced at the knee during extension, independent of knee circumference.
INTRODUÇÃO:
A banda elástica pode afetar o desempenho durante exercícios de alta intensidade, reduzindo a ativação muscular, o que pode influenciar o efeito de potencialização pós-ativação, que depende de alta intensidade para o exercício subsequente que visa potência. Objetivo: Verificar os efeitos agudos no desempenho do salto com contramovimento (SCM) após o agachamento em alta intensidade com e sem o uso da banda elástica de joelhos em sujeitos treinados em força.
MÉTODOS:
Participaram do estudo 14 homens (idade: 24 ± 4 anos, estatura: 176 ± 6 cm, massa corporal: 81 ± 11 kg, 1RM: 107 ± 30 kgf), treinados em força (>3 anos). Foram realizados três SCM antes e após três meio-agachamentos a 90% de 1RM nas condições com e sem a banda elástica de joelhos. Durante o SCM foram avaliados ativação muscular (IEMG) do vasto lateral (VL), glúteo máximo (GM), tempo de salto (TS) e impulso (IMP) por meio da força vertical de reação do solo (FRSv).
RESULTADOS:
Os resultados mostraram que para o TS foi verificada diferença significante entre as condições pós-meio-agachamento (com e sem banda) (P = 0,044, TE = 1,02), sendo que os maiores valores foram observados para a condição sem banda. Para a IEMG de VL foi verificada diferença significante entre as condições pré e pós o meio-agachamento (com banda) (P = 0,029, TE = 1,68), sendo que os maiores valores foram observados para a IEMG com banda. Para a IEMG de GM e para o IMP não foram verificadas diferenças significantes entre as condições.
CONCLUSÃO:
Após a utilização da banda elástica de joelhos durante o exercício agachamento, ocorreu uma redução na participação do vasto lateral durante o salto com contramovimento, afetando o tempo de contato, mas não a produção de impulso, e consequente desempenho.
RESUMO Introdução: A banda elástica pode afetar o desempenho durante exercícios de alta intensidade, redu-zindo a ativação muscular, o que pode influenciar o efeito de potencialização pós-ativação, que depende de alta intensidade para o exercício subsequente que visa potência. Objetivo: Verificar os efeitos agudos no desempenho do salto com contramovimento (SCM) após o agachamento em alta intensidade com e sem o uso da banda elástica de joelhos em sujeitos treinados em força. Métodos: Participaram do estudo 14 homens (idade: 24 ± 4 anos, estatura: 176 ± 6 cm, massa corporal: 81 ± 11 kg, 1RM: 107 ± 30 kgf), trei-nados em força (>3 anos). Foram realizados três SCM antes e após três meio-agachamentos a 90% de 1RM nas condições com e sem a banda elástica de joelhos. Durante o SCM foram avaliados ativação muscular (IEMG) do vasto lateral (VL), glúteo máximo (GM), tempo de salto (TS) e impulso (IMP) por meio da força vertical de reação do solo (FRSv). Resultados: Os resultados mostraram que para o TS foi verificada diferença significante entre as condições pós-meio-agachamento (com e sem banda) (P = 0,044, TE = 1,02), sendo que os maiores valores foram observados para a condição sem banda. Para a IEMG de VL foi verificada diferença significante entre as condições pré e pós o meio-agachamento (com banda) (P = 0,029, TE = 1,68), sendo que os maiores valores foram observados para a IEMG com banda. Para a IEMG de GM e para o IMP não foram verificadas diferenças significantes entre as condições. Conclusão: Após a utilização da banda elástica de joelhos durante o exercício agachamento, ocorreu uma redução na participação do vasto lateral durante o salto com contramovimento, afetando o tempo de contato, mas não a produção de impulso, e consequente desempenho. Palavras-chave: força muscular, desempenho atlético, treinamento de resistência. ABSTRACT Introduction: Knee wraps can affect the muscular performance during high-intensity exercises by reducing muscle activation, which may influence the effect of post-activation potentiation, which depends on high intensity for the following power exercise. Objective: To investigate the acute effects on the performance with counter-movement jump (CMJ) after high-intensity squat with and without the use of knee wraps in resistance trained subjects. Methods: The study included 14 men (aged 24±4 years, height: 176±6cm, weight: 81±11kg, 1RM: 107±30kgf) resistance trained (>3 years). Three SCM were performed before and after three back squats at 90% of 1RM with and without the knee wraps. During the CMJ muscle activation (IEMG) of the vastus lateralis (VL) and gluteus maximus (GM), jump time (JT), and impulse (IMP) through the force of vertical ground reaction (FRSV) were evaluated. Results: The results show statistically significant differences for JT between post-back-squat conditions (with and without wrap) (P=0.044, TE=1.02), whereas the highest values were observed without knee wrap. For IEMG of VL significant difference between pre and post-conditions after back squat (with knee wrap) (P=0.029, TE=1.68) was observed, and the highest values were observed for the IEMG with knee wrap. No significant differences between conditions were observed for IEMG of GM and IMP. Conclusion: After using the knee wraps during the squat exercise, there was a reduction in the involvement of the vastus lateralis during the jump with counter-movement, affecting the contact time, but not the production of impulse and consequent performance.
Many sports have been using different types of accessories in order to increase the safety or performance of athletes. Among these stands out the modalities powerlifting, which presents specific workout accessories: clothes stand and elastic bands? However, the use and efficiency of such accessories still some controversy because of its real efficiency during training and competitions. This controversy is based on the mechanical effect of the elastic components of such equipment, which increases the loading capacity of athletes. This effect of an additional force is also known as carry-over. The carry-over effect is the use of these accessories polemic by two basic principles, the first principle refers to the security provided by these accessories, the second basic principle concerns the improvement of performance. Therefore, this study aimed to conduct a brief review of literature on the biomechanical effects of using the elastic band at the knee during squats in powerlifting. This review seeks to raise the real effects already studied the use of elastic band, their role in assisting the year and possible effects on the mechanical performance.
This study assessed whether opposing compression forces produced by commercially available "compression shorts" affect the repetitive force production capabilities of the thigh muscles during repetitive open- and closed-kinetic-chain exercise tests. Twenty healthy young adults (10 men, age 25.2 +/- 3.8 yrs; 10 women, age 23.2 +/- 4.8 yrs) volunteered to take part in the study. All were recreationally trained and participated in both weight training and endurance training programs in their weekly exercise routines. Testing was conducted using a balanced and randomized treatment design with two experimental conditions consisting of compression shorts (CS) and control (no compression) shorts; thus all subjects served as their own controls. Testing consisted of 3 sets of 50 maximal isokinetic knee extension/ flexion movements at 180[degrees] * sec-1 on a Cybex 6000 dynamometer and the maximal number of reps at 70% 1-RM using a Trusquat exercise machine. No significant differences were found between the CS and control conditions in peak torque or total work performed in the isokinetic knee extension/flexion exercise or in max number of reps performed with the Trusquat. The results indicate that compression garments made for long-term wear and commonly worn by athletes and fitness enthusiasts during training and competition do not contribute to any additional fatigue in repetitive high-intensity exercise tasks.
(C) 1998 National Strength and Conditioning Association
The purpose of this study was to determine the accuracy of using relative muscular endurance performance to estimate 1-RM bench press and squat strength in college football players. NCAA Div. II players (N = 45) were tested after 12 weeks of resistance training in a winter conditioning program. Each subject selected a weight he anticipated to be 70% of l-RM for each lift and performed as many repetitions as possible. Results indicated that players selected weights averaging 71.3 and 68.0% of 1-RM bench press and squat, respectively, and averaged 13.9 and 17.4 repetitions-to-failure. The Mayhew et al. equation significantly underestimated 1-RM bench press while the Epley, Lander, and Brzycki equations significantly overestimated it. In the squat, all equations significantly overestimated 1-RM values. It appears that an exponential relative muscular endurance equation can be used to estimate 1-RM bench press strength in college football players, but none of the equations evaluated were accurate for predicting l-RM squat.
(C) 1995 National Strength and Conditioning Association
Compression shorts have become a very popular item of sports apparel. Few data exist about whether they influence athletic performance. The purpose of this study was to determine whether compression shorts affected vertical jump performance after different fatigue tasks (i.e., endurance, strength, and power). In addition, experiments on the influence of a compression garment on joint position sense at the hip and muscle movement velocity upon landing impact was also studied. Healthy college age men and women participated in the various studies. Subjects were thoroughly familiarized with the jump tests and all other experimental techniques. Jumps were performed on an AMTI force plate which was interfaced to a computer with customized software used to determine jump power. Ten consecutive maximal counter movement jumps with arms held at waist level were performed. The compressive garment had no effect on the maximal power of the highest jump in either men or women. The compressive garment significantly enhanced mean power output in the jump test both before and after different fatigue tasks. The compressive garment enhanced joint position sense at the hip at 45°and 60°of flexion. A compression garment also significantly reduced the vertical velocity of muscle movement upon landing. These data indicate that compression shorts do not improve maximal jump power output. However, an enhanced mean power output during the repetitive maximal jump test was observed when wearing a compression garment. The performance improvement observed may be due to reduced muscle oscillation upon impact, psychological factors, and/or enhanced joint position sense.
The purpose of this study was to determine whether compression shorts affected vertical jump performance. Subjects, 18 men and 18 women varsity volleyball players, were thoroughly familiarized with the jump tests and experimental techniques. Testing utilized compression shorts of normal fit (CS), undersized compression shorts (UCS), and loose fitting gym shorts as the control garment (CT). All tests were conducted on the same day using a balanced, randomized block design to remove day-to-day variation. Jumps were performed on an AMTI force plate interfaced to a computer with customized software to determine jump force and power. Ten consecutive maximal countermovement jumps with hands held at waist level were evaluated. The garments had no effect on maximal force or power of the highest jump. However, mean force and power production over the 10 jumps when wearing the CS were significantly (p < 0.05) higher than CT for both men and women. In men the UCS mean power production was also higher than the CT. The data indicate that compression shorts, while not improving single maximal jump power, have a significant effect on repetitive vertical jumps by helping to maintain higher mean jumping power.
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