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The Effects of a Weight Belt on Trunk and Leg Muscle Activity and Joint Kinematics During the Squat Exercise
Abstract
Fourteen healthy men participated in a study designed to examine the effects of weight-belt use on trunk- and leg-muscle myoelectric activity (EMG) and joint kinematics during the squat exercise. Each subject performed the parallel back squat exercise at a self-selected speed according to his own technique with 90% of his IRM both without a weight belt (NWB) and with a weight belt (WB). Myoelectric activity of the right vastus lateralis, biceps femoris, adductor magnus, gluteus maximus, and erector spinae was recorded using surface electrodes. Subjects were videotaped from a sagittal plane view while standing on a force plate. WB trials were completed significantly faster (p < 0.05) than NWB trials over the entire movement and in both the downward phase (DP) and upward phase (UP). No significant differences in EMG were detected between conditions for any of the muscle groups or for any joint angular kinematic variables during either phase of the lift. The total distance traveled by the barbell both anteriorly and vertically was significantly greater (p < 0.01) in the WB condition than the NWB condition. The velocity of the barbell was significantly greater (p < 0.01) both vertically and horizontally during both the DP and UP in the WB condition as compared with the NWB condition. These data suggest that the use of a weight belt during the squat exercise may affect the path of the barbell and speed of the lift without altering myoelectric activity. This suggests that the use of a weight belt may improve a lifter's explosive power by increasing the speed of the movement without compromising the joint range of motion or overall lifting technique.
... Twenty-one studies assessed EMG of muscles while using LSO [7,8,12,[25][26][27][28][29][30][31][32][33][34][35][36][38][39][40]47,48,51]. The most frequently evaluated muscles included erector spinae (ES), external oblique (EO), and rectus abdominis (RA). ...
... In the study by Thomas et al. [31], whereas the contralateral ES activity decreased by 3.3% on asymmetric loading, the ES activity on the left side increased by 2.9% on symmetric loading. In six of the included studies, no change was observed in the amplitude of back extensor muscle activity [30,32,35,39,40,47]. Orthoses were found to have no effect on median power spectrum frequency and muscular fatigue in the studies by Ciriello and Snook [25], and Majkowski et al. [38]. ...
... One possible reason for this inconsistency may be the different types of LSO used in the included studies. Leather weightlifting belts were used as LSO in four out of six studies that did not report any change in back muscle activity [30,39,40,47], and elastic belts were used in the remaining two [32,35]. Of the eight studies that reported reduced back muscle activity, elastic back supports were used in four [26,34,36,51], non-elastic belts in two [7,12], and leather belts in the remaining two [28,33]. ...
Background:
Wearing lumbosacral orthosis (LSO) is one of the most common treatments prescribed for conservative management of low back pain. Although the results of randomized controlled trials suggest effectiveness of LSO in reducing pain and disability in these patients, there is a concern that prolonged use of LSO may lead to trunk muscle weakness and atrophy.
Purpose:
The present review aimed to evaluate available evidence in literature to determine whether LSO results in trunk muscle weakness or atrophy.
Study design:
This is a systematic review.
Methods:
A systematic search of electronic databases including PubMed, Scopus, ScienceDirect, and Medline (via Ovid) followed by hand search of journals was performed. Prospective studies published in peer-reviewed journals, with full text available in English, investigating the effect of lumbar orthosis on trunk muscle activity, muscle thickness, strength or endurance, spinal force, and intra-abdominal pressure in healthy subjects or in patients with low back pain, were included. Methodological quality of selected studies was assessed by using the modified version of Downs and Black checklist. This research had no funding source, and the authors declare no conflicts of interest-associated biases.
Results:
Thirty-five studies fulfilled the eligibility criteria. The mean and standard deviation of the quality score was 64±9.7%. Most studies investigating the effect of lumbar orthosis on electromyographic activity (EMG) of trunk muscles demonstrated a decrease or no change in the EMG parameters. A few studies reported increased muscle activity. Lumbosacral orthosis was found to have no effect on muscle strength in some studies, whereas other studies demonstrated increased muscle strength. Only one study, which included ultrasound assessment of trunk muscle stabilizers, suggested reduced thickness of the abdominal muscles and reduced cross-sectional area of the multifidus muscles. Out of eight studies that investigated spinal compression load, the load was reduced in four studies and unchanged in three studies. One study showed that only elastic belts reduced compression force compared to leather and fabric belts and ascribed this reduction to the elastic property of the lumbar support.
Conclusion:
The present review showed that the changes in outcome measures associated with muscle work demands were inconsistent in their relation to the use of lumbar supports. This review did not find conclusive scientific evidence to suggest that orthosis results in trunk muscle weakness.
... Kinematic, kinetic, and electromyographic (EMG) studies have reported muscle activation of the lower limb resulting from variations of squat depth (5), foot placement (10,24,25), and training status and training intensity (26). There have also been studies (36) on the impact of squatting with or without a weight belt on trunk muscle activation (TMA). More recently, a number of researchers have reported the effect of instability on TMA and squat performance (2,3,13,20,21,23,27,33). ...
... The majority of the studies reviewed (3,12,13,23,25,28,32,33,36) used an MVIC procedure to normalize EMG data. In studies with repeated measures within the same individual, mean EMG was reported without normalization (2,27). ...
... The use of a supportive abdominal belt or weight belt is common in heavy lifting in weight training and in manual handling tasks. Zink et al. (36) conducted a study to measure the impact of squatting at a high relative load (90% 1RM) with or without a weight belt on joint kinematics and muscle activity of the following muscles: vastus lateralis, biceps femoris, adductor magnus, gluteus maximus, and erector spinae. There were no significant differences for mean EMG and time to peak EMG for any of the muscles in the concentric or eccentric phase of a parallel squat at 90% 1RM with a weight belt compared with no weight belt. ...
The purpose of this article was to review a series of studies (n = 18) where muscle activation in the free barbell back squat was measured and discussed. The loaded barbell squat is widely used and central to many strength training programs. It is a functional and safe exercise that is obviously transferable to many movements in sports and life. Hence, a large and growing body of research has been published on various aspects of the squat. Training studies have measured the impact of barbell squat loading schemes on selected training adaptations including maximal strength and power changes in the squat. Squat exercise training adaptations and their impact on a variety of performance parameters, in particular countermovement jump, acceleration, and running speed, have also been reported. Furthermore, studies have reported on the muscle activation of the lower limb resulting from variations of squat depth, foot placement, training status, and training intensity. There have also been studies on the impact of squatting with or without a weight belt on trunk muscle activation (TMA). More recently, studies have reported on the effect of instability on TMA and squat performance. Research has also shown that muscle activation of the prime movers in the squat exercise increases with an increase in the external load. Also common variations such as stance width, hip rotation, and front squat do not significantly affect muscle activation. However, despite many studies, this information has not been consolidated, resulting in a lack of consensus about how the information can be applied. Therefore, the purpose of this review was to examine studies that reported muscle activation measured by electromyography in the free barbell back squat with the goal of clarifying the understanding of how the exercise can be applied.
... 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. ...
... 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. Prior research does not provide a general consensus for the level of muscle activity in the trunk and back extensor muscles when squatting with and without a belt (Bauer, Fry, & Carter, 1999;Kurustien, Mekhora, Jalayondeja, & Nanthavanij, 2014;Lander, Simonton, & Giacobbe, 1990;McGill, Norman, & Sharratt, 1990;Miyamoto, Iinuma, Maeda, Wada, & Shimizu, 1999;Warren, Appling, Oladehin, & Griffin, 2001;Zink, Whiting, Vincent, & McLaine, 2001). Elastic knee wraps however, have been shown to significantly increase (p < 0.05) the muscle activity of the vastus lateralis muscle and gluteus maximus activity at 65% 1RM and 90% 1RM ...
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.
... This application aims to describe the timing and relative degree of active muscle activity during resistance exercises, often comparing activity between different exercises (Escamilla et al., 1998) or exercise variations (Zink, Whiting, Vincent, & McLaine, 2001). This approach requires an analysis system capable of recording synchronized sEMG and biomechanical measurement signals that can ensure that sEMG data can be referenced against a defined period or movement interval. ...
... To our knowledge this is the first study to establish reliability of a flexible electrogoniometer device for a dynamic resistance exercise. The maximum knee angles in this study (123.5 + 11.18) were slightly greater than those previously reported (113.9 + 10.08: Zink et al., 2001;98.0 + 13.08: Fry, Smith, & Schilling, 2003) in studies analysing knee angular displacement using digital video analysis during Olympic style barbell squatting. The lower values in these studies are likely to be due to the exercise being defined as a ''parallel'' squat, where the hips descend to the same level as the knee, and not below the knee in the full squat technique performed in this study. ...
An analysis system for barbell weightlifting exercises is proposed to record reliable performance and neuromuscular responses. The system consists of surface electromyography (sEMG) synchronized with electrogoniometry and a barbell position transducer. The purpose of this study was to establish the reliability of the three components of the system. Nine males (age 28.9 ± 4.8 years, mass 85.7 ± 15.1 kg) performed squat exercise at three loads on three separate trial days. A data acquisition and software system processed maximal knee angle (flexion), mean power for the concentric phase of squat exercise, and normalized root mean square of the vastus lateralis. Inter-trial coefficients of variation for each variable were calculated as 5.3%, 7.8%, and 7.5% respectively. In addition, knee joint motion and barbell displacement were significantly related to each other (bar displacement (m) = 1.39-0.0057 × knee angle (degress), with goodness-of-fit value, r² = 0.817), suggesting knee goniometry alone can represent the kinematics of a multi-joint squat exercise. The proven reliability of the three components of this system allows for real-time monitoring of resistance exercise using the preferred training methods of athletes, which could be valuable in the understanding of the neuromuscular response of elite strength training methods.
... The subjects were asked to refrain from vigorous lower body exercise 48 h before the formal examination. Since studies had shown that the protective equipment could improve movement velocity [50], subjects were prohibited from wearing any protective equipment (wrist guard, belt, or knee strap) during the examination to ensure uniformity and accuracy of measurements. ...
Recent advances in training monitoring are centered on the statistical indicators of the concentric phase of the movement. However, those studies lack consideration of the integrity of the movement. Moreover, training performance evaluation needs valid data on the movement. Thus, this study presents a full-waveform resistance training monitoring system (FRTMS) as a whole-movement-process monitoring solution to acquire and analyze the full-waveform data of resistance training. The FRTMS includes a portable data acquisition device and a data processing and visuali-zation software platform. The data acquisition device monitors the barbell's movement data. The software platform guides users through the acquisition of training parameters and provides feedback on the training result variables. To validate the FRTMS, we compared the simultaneous measurements of 30-90% 1RM of Smith squat lifts performed by 21 subjects with the FRTMS to similar measurements obtained with a previously validated three-dimensional motion capture system. Results showed that the FRTMS produced practically identical velocity outcomes, with a high Pear-son's correlation coefficient, intraclass correlation coefficient, and coefficient of multiple correlations and a low root mean square error. We also studied the applications of the FRTMS in practical training by comparing the training results of a six-week experimental intervention with velocity-based training (VBT) and percentage-based training (PBT). The current findings suggest that the proposed monitoring system can provide reliable data for refining future training monitoring and analysis.
... The experiment was carried out in a total of two steps with an interval of 3 days [22,23]. In the first step, the one repetition maximum (1 RM) of the participant's HBBS and LBBS was measured. ...
This study aimed to investigate the effect of the load and bar position on trunk and lower extremity muscle activity during squat exercise. High bar back squats (HBBS) and low bar back squats (LBBS) were performed in random order at 50%, 60%, and 70% loads of one repetition maximum by 28 experienced healthy adult men who had been performing squats for at least one year. Before the experiment, the maximal voluntary contraction of the vastus medialis, vastus lateralis, rectus femoris, biceps femoris, rectus abdominis, transverse abdominis, external oblique, and erector spinae muscles was measured by means of surface electromyography. In addition, eccentric and concentric exercises were performed for 3 s each to measure the muscle activity. There was a significant difference in muscle activity according to the load for all muscles in the eccentric and concentric phases (p < 0.05), indicating that muscle activity increased as the load increased. In addition, in the comparison between HBBS and LBBS, significant differences were shown in all lower extremity muscles and all trunk muscles except for the external oblique in the concentric phase according to the bar position (p < 0.05). HBBS showed a higher muscle activity of the lower extremity in the eccentric and concentric phases than in LBBS, while LBBS showed a higher muscle activity of the trunk muscle in the eccentric and concentric phases than in HBBS (p < 0.05). HBBS requires more force in the lower extremity than LBBS and is particularly advantageous in strengthening the muscular strength of the quadriceps. In contrast, LBBS requires more muscle activity in the trunk than HBBS and is more effective in carrying heavier loads because of the advantage of body stability. This study suggests that rehabilitation experts apply the bar position and load as important variables affecting the intensity and method of training for target muscle strengthening of the lower extremities and trunk.
... It might be attributed to the improved confidence during squatting with a belt. [29,30] However, the exact mechanisms responsible for this reduced time remain unclear and require further research. When using straps in combination with a belt, we found that deadlift completion time was further reduced ( Table 2). ...
Both weightlifting belts and wrist straps are commonly used weightlifting training aids but their effects on deadlift kinematics and performance were still not known. This study examined the effects of weightlifting belts and wrist straps on the kinematics of the deadlift exercise, time to complete a deadlift and rating of perceived exertion (RPE) in male recreational weightlifters. This study used a repeated-measures, within-subjects design. Twenty male healthy recreational weightlifters (mean age ± standard deviation = 23.1 ± 2.5 years) were recruited from 2 local gyms and the Education University of Hong Kong between January and April 2021. All participants used various combinations of belt and straps during a conventional deadlift. The hip and knee flexion, cervical lordosis, thoracic kyphosis and lumbar lordosis angles and time to complete a deadlift were measured using video analysis software. RPE was also recorded. Wearing both a belt and wrist straps was found to reduce knee flexion angle (P < .001), but not hip flexion angle (P > .05), during the setup phase of the deadlift compared to wearing no aid. Wearing straps alone exaggerated thoracic kyphosis in the lockout phase of the deadlift compared to wearing a belt alone (P < .001). No changes were seen in cervical and lumbar lordosis angles when using any or both of the weightlifting aids. Additionally, the participants completed deadlifts faster when wearing both a belt and straps (P = .008) and perceived less exertion when wearing a belt and/or straps (P < .001). Weightlifting belts and wrist straps, when using together, have positive effects on the kinematics of deadlift, time to complete a deadlift and RPE in male recreational weightlifters. Trainers should recommend the use of a belt and straps together, but not straps alone, to recreational weightlifters when performing deadlift 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.
... sequência pedagógica do movimento), seja realizando um trabalho específico (aquisição de força muscular de grupamentos musculares sinergistas ao movimento), que auxiliem no desempenho de um movimento específico e que contribuam para melhorar processos bioenergéticos (e.g. eficiência na utilização de substratos oriundos do sistema fosfágeno) do atleta visando otimizar o desempenho no levantamento competitivo (16)(17)(18), utilizando acessórios que promovam redução de forças compressivas na coluna e estabilização pélvica durante os levantamentos, por meio do aumento da pressão intra-abdominal (19). Por esse motivo, a utilização desses equipamentos acessórios é uma prática comum entre os atletas. ...
Introduction: The management of strength training variables and chronic exposure to high intensities and physiological training loads can impact the prevalence of musculoskeletal injuries in powerlifting athletes.
Purpose: To estimate the prevalence of injuries in Brazilian powerlifting athletes, and subsequently identify strength training variables that predict the prevalence of musculoskeletal injuries.
Methods: Observational, sectional study with a convenience sample, which included 37 male powerlifting athletes. The prevalence of musculoskeletal injuries (outcome) was self-reported and aspects of training practices were examined in relation to the occurrence of injuries. To detect the predictive variables of the prevalence of injuries, multivariate logistic regression (stepwise forward) was used and the odds ratio (OR) and the coefficient of determination (Nagelkerke R²) were calculated.
Results: The average age of the sample was 32.10 (± 7.53) years and the average experience time was 8.76 (± 3.54) years. Age (OR 1.23; 95% CI [1.11-1.41]), sessions per week (OR 8.66; 95% CI [3.06-32.55]) and use of chains (OR 6.50 ; 95% CI [1.86-26.04]) determined 48% of the prevalence of musculoskeletal injuries in powerlifting athletes (R²=0.48). The lumbopelvic joint (66.67% joint + 18.20% muscular) and glenohumeral (24.24% joint + 42.42% muscular) were the regions with the highest prevalence of injury among athletes.
Conclusion: The results were in accordance of previous studies and indicate that adequate volume and intensity management and monitoring of predictive factors for injuries are recommended both to increase performance and to mitigate the prevalence of musculoskeletal injuries in powerlifting athletes.
... However, one study showed muscle group-specific adaptations of hamstring power after squats with superimposed WB-EMS (Wirtz et al., 2016). Despite notable co-activation (Zink et al., 2001), it has been reported that the activation of hamstring muscles is not affected by additional loading during squat exercise (Nuzzo and McBride, 2013). EMS can lead to higher hamstring muscle activation during lengthening and shortening, which would then results in higher hamstring maximum force in the WB-EMS training group. ...
Background: Whole-body electromyostimulation (WB-EMS) gained increasing interest in sports within recent years. However, few intervention studies have examined the effects of WB-EMS on trained subjects in comparison to conventional strength training. Objective: The aim of the present mini-meta-analysis of 5 recently conducted and published randomized controlled WB-EMS trails of our work group was to evaluate potentially favorable effects of WB-EMS in comparison to conventional strength training. Methods: We included parameter of selected leg muscle's strength and power as well as sprint and jump performance. All subjects were moderately trained athletes [>2 training sessions/week, >2 years of experience in strength training; experimental group (n = 58): 21.5 ± 3.3 y; 178 ± 8 cm; 74.0 ± 11 kg; control group (n = 54): 21.0 ± 2.3 y; 179.0 ± 9 cm; 72.6 ± 10 kg]. The following WB-EMS protocols were applied to the experimental group (EG): 2 WB-EMS sessions/week, bipolar current superimposed to dynamic exercises, 85 Hz, 350 μs, 70% of the individual pain threshold amperage. The control groups (CG) underwent the same training protocols without WB-EMS, but with external resistance. Results: Five extremely homogenous studies (all studies revealed an I2 = 0%) with 112 subjects in total were analyzed with respect to lower limb strength and power in leg curl, leg extension and leg press machines, sprint—and jump performance. Negligible effects in favor of WB-EMS were found for Fmax of leg muscle groups [SMD: 0.11 (90% CI: −0.08, 0.33), p = 0.73, I2 = 0%] and for CMJ [SMD: 0.01 (90% CI: −0.34, 0.33), p = 0.81, I2 = 0%]. Small effects, were found for linear sprint [SMD: 0.22 (90% CI: −0.15, 0.60), p = 0.77, I2 = 0%] in favor of the EMS-group compared to CON. Conclusion: We conclude that WB-EMS is a feasible complementary training stimulus for performance enhancement. However, additional effects on strength and power indices seem to be limited and sprint and jump-performance appear to be benefiting only slightly. Longer training periods and more frequent application times and a slightly larger stimulus could be investigated in larger samples to further elucidate beneficial effects of WB-EMS on performance parameters in athletes.
... A potential problem with this suggestion is that in some cases, multiple single-joint exercises will need to be used to elicit a similar physiological response as one multijoint exercise. For example, the barbell squat engages the gluteus maximus, quadriceps, hamstrings, adductors, and erector spinae (Contreras, Vigotsky, Schoenfeld, Beardsley, & Cronin, 2015;Escamilla et al., 2001;Zink, Whiting, Vincent, & McLaine, 2001). To target the same muscle groups, a coach may prescribe machine knee extension, knee curl, adduction, and back extension, which will result in a longer workout with more volume. ...
Research in aerobic exercise has linked the affective responses (pleasure–displeasure) experienced during exercise to future exercise participation. While this is yet to be confirmed in anaerobic activities, it can be inferred that making resistance exercise (RE) more psychologically rewarding is an important consideration. The purpose of this article is to review the acute effects of RE on affect, anxiety, and mood and to draw conclusions on how to maximize feelings of pleasure in an effort to increase rates of participation. This review provides evidence to support lower training volumes performed at low to moderate intensities (50–70% 1RM) with long inter-set rest intervals (90–150 s). Additional recommendations are provided based on physiological and theoretical support, but there is a strong need for more research on the affective experience of RE.
... В основном оценивалась амплитуды паттерна произвольной активности [37][38][39][40][41]. В некоторых исследованиях сообщается о развитии мышечной слабости при использовании ортезов -на 4 % в мышце, выпрямляющей позвоночник [38], и уменьшении её активности справа при симметричной нагрузке [42]. Сообщается об изменении активности мышц на 2-3 % либо отсутствии какого-либо влияния под действием ортезов [43,44,45]. ...
Our literature review analyzes the available studies on the effect of long- and short-term lumbo-sacral orthotic (LSO) treatment on the muscles of the back. We reviewed the existing diagnostic approaches to evaluation of muscle changes, including surface EMG, measurements of muscle strength and tolerance, and findings on muscle ultrasound study. It has been revealed that none of the available works confirmed a significant negative effect of LSO, both by short- and long-term application, or atrophic changes in the muscles. Thus, we may conclude that there are no significant data on the effect of the LSO treatment on the main parameters that are measured and reflect spinal muscles weakness and/or atrophy.
... Torso postural devices have been developed to combat negative torso posture occurring when engaging in activities such as squatting to lift an object. The back belt, a frequently studied torso postural support device, may improve the posture of the spine when lifting boxes (Giorcelli, Hughes, Wassell, & Hsiao, 2001); however, there is little to no effect in hip and knee kinematics (Zink, Whiting, Vincent, & McLaine, 2001). Through haptic feedback, torso postural devices have demonstrated the ability to improve posture of the torso (Zheng & Morrell, 2010;O'Brien & Azrin, 1970); yet, to the authors' knowledge, there has not been a study on the effect of torso postural devices on hip and knee kinematics. ...
This study was constructed to assess the influence of wearing semi-soft exoskeletons on hip and knee kinematics when engaging in a box lifting task. Six healthy college aged students (age: 21.7 ± 2.3; gender: 4 males, 2 females; height: 177.0 ± 3.4 cm; weight: 77.1 ± 17.9 kg; hand dominance: all right) completed box lifting tasks (at 10% and 20% of their body weight) while wearing no exoskeleton and two exoskeleton designs. Lifting a box at 20% body weight increased perceived exertion and was associated with poor hip and knee kinematics in some conditions. Wearing the StrongArm® V22 ERGOSKELETON without hand cables may diminish some of the poor kinematics associated with lifting objects.
... The data of these studies implies that the subjects were able to perform the lifting tasks much more rapidly during belted conditions. Further, Zink et al. (54) demonstrated that the use of back belts increased the velocity of bar movement while performing the squat exercise. ...
... Escamilla et al. (15) reported increased EMG activity in the rectus abdominis when the belt was used in the deadlift and an increase in external oblique activity when no belt was used. Others (57) reported no significant difference in EMG activity when using a belt while participants performed the squat at 90% of 1RM. Lander et al. (35) reported increased muscle activity by 8.3-23.5% in the rectus abdominis, 11.6-22.9% in the erector spinae, and 13.4-44.2% in the external obliques without using a belt while performing the squat. ...
THIS ARTICLE WILL REVIEW THE EFFICACY OF SEVERAL DIFFERENT WEIGHT TRAINING AIDS THAT ARE AVAILABLE FOR USE BY RECREATIONAL WEIGHT TRAINERS AND ALSO COMPETITIVE ATHLETES IN THE SPORTS OF WEIGHTLIFTING AND POWERLIFTING. SOME OF THESE AIDS HAVE BEEN INVESTIGATED BY RESEARCHERS WHILE INFORMATION REGARDING THE USE OF OTHERS HAS BEEN LEFT TO PRACTICAL EXPERIENCE. THIS REVIEW WILL DISCUSS THE USE AND EFFECTIVENESS OF MANY WEIGHT TRAINING AIDS, THEREBY OFFERING PRACTITIONERS THE ABILITY TO MAKE AN INFORMED DECISION ON THEIR USE.
... Zink et al. 23 evidenciaram em 14 indivíduos treinados, a condição de agachamento sem e com cinto força. O cinto não modificou a atividade muscular de músculos de membros inferiores, e eretores da coluna, contudo é notável o aumento de velocidade durante as fases do agachamento comparado a condição sem cinto abdominal, sendo uma possibilidade para treinamentos visando maior produção de trabalho e potência. ...
Revista UNIANDRADE 16(1): 7-13 7 Resumo — O exercício de agachamento impõe diferentes sobrecargas a coluna vertebral e atividade muscular do tronco. Desta forma, diversos estudos trazem mensurações de destes dados principalmente referidos a coluna lombar, local cotidianamente mais sobrecarregado. O objetivo deste trabalho foi realizar uma pesquisa descritiva exploratória e revisar artigos que analisaram sobrecarga articular na coluna vertebral e atividade muscular do tronco. A execução apropriada do agachamento é segura para reabilitação e treinamento de força, porém técnicas inapropriadas e excesso de carga podem causar problemas em tecidos moles como fratura de platô vertebral, prolapsos, extrusão e hérnias de disco. O conhecimento dos aspectos biomecânicos do agachamento como sobrecargas a coluna vertebral e atividade muscular do tronco, podem esclarecer na aplicação para fisioterapeutas, educadores físicos e médicos. Palavras-chave: agachamento, biomecânica, coluna vertebral. Abstract — The squat is a multi-joint exercise that overloads the spine and works with the trunk muscle activity. Thus, many papers measure that carries and they effects on the spine, specially the on lumbar spine that overload daily constantly. The aim of this paper was to do an exploratory descriptive research and review the papers that analyzed joint load and trunk muscle activity. The squat technique is applied to rehabilitation and strength training programs, but inappropriate squat techniques and overweight may lead to several issues, such as end-plate fracture, protrusion, extrusion and disc herniation. The biomechanics knowledge like spine joint load and trunk muscle activity are fundamental and clarifies the squat prescription for physical therapists, physical educators and physicians.
... Regular training with unilateral exercise (PS) has been demonstrated to be equally effective to training with bilateral exercise (BS) in previously untrained men and women (19). Previous research has investigated trunk and lower limb muscle activity during acute bilateral dynamic exercise (BS exercise [3,7,18,22,25,32]), and acute bilateral and unilateral isometric exercise (knee extension exercise [24,26,27]) using surface electromyography (sEMG). However, studies of sEMG activity during dynamic unilateral exercise (e.g., PS) are not as frequent (16). ...
Unilateral and bilateral lower-body heavy resistance exercises (HREs) are used for strength training. Little research has examined whether muscle activation and testosterone (TES) responses differ between these exercises. Our purpose was to compare the effects of unilateral and bilateral lower-body HRE on muscle activity using surface electromyography (sEMG) and TES concentrations. Ten resistance-trained, college-aged male athletes (football, track and field) completed 5 testing sessions in which bilateral (back squat [BS]) and unilateral (pitcher squat [PS]) exercises were performed using a counterbalanced design. Sessions 1 and 2 determined estimated maximum strength (10 repetition maximum [10RM]) in the BS and PS. During testing session 3, muscle activation (sEMG) was measured in the right vastus lateralis, biceps femoris, gluteus maximus, and erector spinae (ES) during both BS and PS (stance leg) exercises. In sessions 4 and 5, total TES concentrations (nanomoles per liter) were measured via blood draws at baseline (preexercise), 0, 5, 10, 15, and 30 minutes postexercise after 4 sets of 10 repetitions at the 10RM. Separate repeated-measures analyses of variance examined differences in sEMG and TES between BS and PS (p < 0.05). The sEMG amplitudes were similar (p = 0.80) for BS (0.22 ± 0.06 mV) and PS (0.20 ± 0.07 mV). The TES responses were also similar (p = 0.15) between BS (21.8 ± 6.9 nmol·L(-1)) and PS (26.2 ± 10.1 nmol·L(-1)). The similar lower limb and back sEMG and TES responses may indicate that the neuromuscular and hormonal demands were comparable for both the BS and PS exercises despite the absolute work being less in the PS. The PS exercise may be an effective method for including unilateral exercise into lower-body resistance training when designing training programs for ground-based activities.
... Additionally, the stability ball back extension (BE) has been studied by Drake et al. (13) and it was discovered that muscle activity was 36.7% of MVC at the L5 vertebrae, 40.7% at the L3 vertebrae, and 50.0% at the T9 vertebrae. Previous investigations have also reported the amount of muscle activity produced during variations of the SQ and DL (1,3,12,14,33). During the concentric phase of SQs at 90% of one-repetition maximum (1RM), it was reported that the erector spinae at the L3–L4 level were stimulated at approximately 55.0% of peak EMG activity (33). ...
The purpose of this investigation was to compare trunk muscle activity during stability ball and free weight exercises. Nine resistance-trained men participated in one testing session in which squats (SQ) and deadlifts (DL) were completed with loads of approximately 50, 70, 90, and 100% of one-repetition maximum (1RM). Isometric contractions during 3 stability ball exercises (quadruped (QP), pelvic thrust (PT), ball back extension (BE)) were also completed. During all exercises, average integrated electromyography (IEMG) from the rectus abdominus (RA), external oblique (EO), longissimus (L1) and multifidus (L5) was collected and analyzed. Results demonstrate that when expressed relative to 100% DL 1RM, muscle activity was 19.5 +/- 14.8% for L1 and 30.2 +/- 19.3% for L5 during QP, 31.4 +/- 13.4% for L1 and 37.6 +/- 12.4% for L5 during PT, and 44.2 +/- 22.8% for L1 and 45.5 +/- 21.6% for L5 during BE. IEMG of L1 during SQ and DL at 90 and 100% 1RM, and relative muscle activity of L5 during SQ and DL at 100% 1RM was significantly greater (P < or = 0.05) than in the stability ball exercises. Furthermore, relative muscle activity of L1 during DL at 50 and 70% 1RM was significantly greater than in QP and PT. No significant differences were observed in RA and EO during any of the exercises. In conclusion, activity of the trunk muscles during SQs and DLs is greater or equal to that which is produced during the stability ball exercises. It appears that stability ball exercises may not provide a sufficient stimulus for increasing muscular strength or hypertrophy; consequently, the role of stability ball exercises in strength and conditioning programs is questioned. SQs and DLs are recommended for increasing strength and hypertrophy of the back extensors.
Water polo is a full body contact sport. It is the combination of swimming, rugby, soccer, and basketball. The basic skills to be mastered in water polo are swimming, water trapping, and ball controlling using hands while floating in the water supported by egg-beater foot movement, where the leg endurance is the main point to perfect this technique. Athletes need leg endurance to float and swim during the game. This study is a literature review aimed at analyzing water polo athletes’ training using weighted jacket and weighted belt in water on their strength and leg endurance. The data were collected from research results published in national and international journals from 1991 to 2019. Therefore, the data were analyzed using content analysis. The review result revealed that the strategy to combine weighted jacket and weighted belt to train water polo athletes’ leg endurance was more effective. Weighted belts were worn around the athlete's waist, and heavy objects that were generally used for scuba diving were placed on belts. On the other hand, weighted jackets must be placed directly below the waist and the weight is suspended between the legs. The jacket with soft, durable, and waterproof material can be adjusted to the athlete's body size. The use of weighted jacket and weighted belt training media in water polo affected the strength and leg endurance of water polo athletes directly.
Background:
A well-known supportive treatment for acute nonspecific back pain, elastic back support belts, are valued for their ability to accelerate natural self-healing, but there are concerns of a deconditioning effect due to their reliance on passive stabilization.
Methods:
To evaluate the systematic effects of elastic abdominal belts on the trunk musculature, a total of 36 persons with acute lumbar back pain (no longer than one week) were divided into two groups: an abdominal belt wearing group (B) and a non-abdominal belt wearing control group (C). All were examined over a period of three weeks at three time points: T1 just after assignment, T2 one week later, and T3 further two weeks later. Surface EMG (sEMG) was used to record trunk muscle activation when walking on a treadmill at walking speeds of 2, 3, 4, 5, and 6 km/h. Similarly, pain intensity (VAS) and functional impairment (ODI) over time were recorded in both groups.
Results:
Over the observation period, a slight advantage for decreased pain intensity (C: p<0.05 T2 vs. T1; B: p<0.01 T2 vs. T1, p<0.05 T3 vs. T1) and decreased functional impairment (Cohen's d vs. T1, C: T2 0.45, T3 0.86; B: T2 1.1, T3 1.0) was observed for the belt group. For the belt group both oblique abdominal muscles exhibited significantly lower sEMG throughout the observation period (external abdominal oblique muscle: (T1), T2, (T3), internal abdominal oblique muscle: T1, (T2), (T3)) and the sEMG for the back muscles ranged from unchanged to slightly elevated for this group, but never reached statistical significance.
Discussion:
The reduced abdominal amplitude levels in the belt group likely result from the permanent elastic stabilization provided by the belt: the required elevated intra-abdominal pressure to enhance spinal stability is then provided by lessened abdominal muscle activity complemented by the belt's elastic support. With regard to the back muscles, the belt, due to its movement-restricting effect, tends to activate the paravertebral musculature. In this respect, the effect of elastic abdominal belts on the trunk muscles is not uniform. Therefore, the present results suggest that the effect of elastic abdominal belts appears to be more of a temporary neutral alteration of trunk muscle coordination, with some trunk muscles becoming more active and others less, and not a case of uniform deconditioning as is suspected.
Introduction: The use of back support is one of the common methods aimed to prevent low back pain. The purpose of the present study was to investigate the effect of wearing a lumbosacral support on lumbar spine velocity and torque in six directions during combined trunk motion. Materials and Methods: In this interventional study, 30 young healthy men were selected simply from convenient samples. They were asked to stand in Isostation B200 system and perform three-dimensional trunk motion against a resistance of 50% of maximal voluntary contraction torque while wearing or not wearing a lumbosacral support. Under each condition of test, five successive motions of trunk were performed in downward direction (as flexion, right lateral flexion, and right rotation) and upward direction (as extension, left lateral flexion, and left rotation), and the variables of average velocity and average torque were recorded during motion. Results: With the use of a lumbosacral support, average velocity was significantly increased in flexion (P=0.015) and extension (P=0.005), but no significant changes were found in other directions (P>0/05). Back support decreased average torque of right rotation significantly (P=0.006), but did not significantly changed this variable in other directions (P>0/05). Conclusion: Wearing a lumbosacral support can increase velocity in sagittal plane. Decreased rotation torque of trunk, as a result of using a back support, may reduce the twisting forces on lumbar spine joints.
Resumo: O objetivo deste estudo foi verificar a influência de três diferentes alturas dos calcanhares no agachamento livre com barra. Foram avaliados 10 sujeitos, sem lesões músculo-esqueléticas. Para mensuração das variáveis cinemáticas, cinéticas e eletromiográficas foi utilizado o Sistema Peak Motus. Os resultados não mostraram diferenças significativas nas variáveis cinemáticas (ângulos articulares e velocidade escalar), força vertical de reação do solo e atividade mioelétrica para os músculos vasto lateral, reto femoral, eretor lombar, glúteo máximo e bíceps femoral entre as três condições (sem apoio para o calcanhar e com apoio de 15 e 30mm), exceto para os ângulos máximos da articulação do tornozelo entre as condições (sem apoio e com apoio 30mm). Sugere-se que a utilização do apoio nos calcanhares está mais relacionada a uma estratégia de variação do exercício agachamento visando reduzir a sobrecarga na articulação do joelho e contribuindo para a manutenção do equilíbrio na execução, sem comprometer a participação muscular. Palavras Chave: Agachamento livre, Força de reação do solo, EMG, Cinemática. Abstract: The purpose of this study was to verify the influence of heel supports on performance of the barbell squat exercise. Ten subjects without any history of musculoskeletal injury were assessed. The Peak Motus System was utilized for measurement of kinematics, kinetics, and electromyography variables. The results did not demonstrate significant differences in the kinematics variables (joint angles and scaled velocity), vertical ground reaction force, and muscular activity of the vastus lateralis, rectus femoris, erector spinae, gluteus maximus, and biceps femoris between the three conditions (no heel support, and 15 and 30 mm heel support), with the exception of the maximal angle of the ankle between the conditions (no heel support and 30 mm). It is suggested the use of heel support is related to a variation strategy of the squat exercise aiming to reduce the overload on the knee joint while contributing to the maintenance of balance, without compromising muscle activity Keywords: Barbell squat, Ground reaction force, EMG, Kinematic.
The purpose of this study were to analyze the levels of activation of the gluteus maximus, biceps femoris, rectus femoris and vastus medialis muscles and to analyze the subjective perception of strength between hip extensor muscles in three different forms of execution of the hip extension exercise (with knee extension (KE); with knee flexion (KF), with knee and hip extension (KHE)). Eleven experienced females without neuro-muscleskeletal injuries served as subjects. Data were acquired using surface electromyographic (1980 Hz) and Borg's scale. The electromyographic data show higher activity of the biceps femoris in all the analyzed exercises and the biggest activity of the gluteus maximus occurred in KHE exercise. The subjective perception of strength was bigger for the posterior thigh muscles in KF and KE exercise, and for gluteus maximus in the KHE.
summary: This manuscript reviews the literature on the effects of the use of back belts in industrial and strength and conditioning applications. Although the results are mixed, the preponderance of evidence supports some use of back belts during resistance training.
(C) 2006 National Strength and Conditioning Association
We describe a new, functional surgical technique, known as 'encircling mesh', designed to address abdominal wall problems. The rationale of the procedure is to connect the anterior and posterior trunk muscle compartments by means of a purpose built polypropylene mesh that encloses a belt shifted posteriorly across the spine subcutaneously, through use of a disposable introducer. The technical details and a case presentation, with specific references to the cosmetic and functional outcomes are described.
The purpose of this study was to examine the effectiveness of weight-belts during multiple repetitions of the parallel back squat exercise. Five subjects were filmed (50 fps) as they performed eight consecutive trials at each of two weight-belt conditions [with belt = WB, without belt = WOB] in random order at their eight-repetition maximum effort. Other parameters examined were ground reaction forces, intra-abdominal pressure (IAP), and mean electromyography (mEMG) for the external oblique (EO), erector spinae (ES), vastus lateralis (VL), and bicep femoris (BF) muscles. All parameters were collected and interfaced to a computer via an A/D converter. WB repetitions were generally performed faster than WOB repetitions, especially by the later repetitions (3.34 vs 3.56 s). WB IAP values were consistently greater (P less than 0.05) than WOB values by 25-40%. IAP increased by approximately 11.5% from the first to the last repetitions. No differences were observed for ES and EO mEMG for belt usage, but values increased by up to 20% across repetitions. Several differences were observed between WB and WOB for the VL and BF mEMG, with WB values being significantly greater. These data suggest that a weight-belt aids in supporting the trunk by increasing IAP, and that any differential effect due to wearing a weight-belt did not occur over eight repetitions.
The purpose of this study was to determine whether abdominal belts such as those prescribed to industrial workers reduced trunk muscle activity and/or increased intra-abdominal pressure (IAP). In this study, six subjects lifted loads (72.7 to 90.9 kg) both with and without wearing a weightlifter belt. In addition, further trial conditions required that subjects lifted both with the breath held or continuously expiring on lifting effort. Dynamic hand loads were recorded together with intra-abdominal pressure (IAP) and abdominal, intercostal and low back EMG. Every subject demonstrated an increase in IAP when wearing the belt during both breathing conditions: 99 mmHg with no belt; 120 mmHg wearing belt (p less than 0.0001). However, it was also found that significant increases in IAP occurred (p less than 0.017) when the breath was held versus exhaling with or without the belt. One would expect that if the belt relieved either the direct compressive load on the spine or assisted IAP to produce an extensor moment then this would be reflected in diminished extensor muscle activity. Erector spinae activity tended to be lower with the breath held suggesting a reduced load on the lumbar spine although wearing a belt did not augment this reduction. In the case studies with subjects wearing an ergogenic corset designed for use by industrial manual materials handlers, perceptions of improved trunk stability were reported. However, the muscle activity and IAP results of this study during short duration lifting tasks make it difficult to justify the prescription of abdominal belts to workers.
The purpose of this study was to examine the effectiveness of weight-belts during the performance of the parallel squat exercise. Six subjects were filmed (40 fps) as they performed three trials at each of three belt conditions (NB, none; LB, light; HB, heavy) in random order and three load conditions (70, 80, 90% 1RM (one repetition maximum] in increasing order. The parameters examined were collected and interfaced to a computer via an analog-to-digital (A/D) converter: ground reaction forces, intra-abdominal pressure (IAP), and EMG for the rectus abdominus (RA), external oblique (EO), and erector spinae (ES) muscles. Most differences were observed during the 90% 1RM condition, and only they are presented in this paper. Maximum IAP values were always greater (P less than 0.05) for the weight-belt conditions (LB, 29.2; HB, 29.1 greater th an NB, 26,8 kPa). Similar results were observed for the mean IAP. The integrated EMG (iEMG) activity of the muscles and adjusted mean values for back compressive force and back muscle force followed a similar but opposite pattern, with NB being the greatest. ES mEMG/(L5/S1) values for HB (18.1%) were the least, followed by LB (20.01%) and NB (22.3%). Few differences were observed between belt types. These data suggest that a weight-belt can aid in supporting the trunk by increasing IAP.
Eight Swedish national class weightlifters performed "high-bar" squats and six national class powerlifters performed "low-bar" squats, with a barbell weight of 65% of their 1 RM, and to parallel- and a deep-squatting depth. Ground reaction forces were measured with a Kistler piezo-electric force platform and motion was analyzed from a video record of the squats. A computer program based on free-body mechanics was designed to calculate moments of force about the hip and knee joints. EMG from vastus lateralis, rectus femoris, and biceps femoris was recorded and normalized. The peak moments of force were flexing both for the hip and the knee. The mean peak moments of force at the hip were for the weightlifters 230 Nm (deep) and 216 Nm (parallel), and for the powerlifters 324 Nm (deep), and 309 Nm (parallel). At the knee the mean peak moments for the weightlifters were 191 Nm (deep) and 131 Nm (parallel), and for the powerlifters 139 Nm (deep) and 92 Nm (parallel). The weightlifters had the load more equally distributed between hip and knee, whereas the powerlifters put relatively more load on the hip joint. The thigh muscular activity was slightly higher for the powerlifters.
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