Muscle-Specific Effective Mechanical Advantage and Joint Impulse in Weightlifting

Lifting greater loads during weightlifting exercises may theoretically be achieved through increasing the magnitudes of net joint impulses or manipulating the joints’ effective mechanical advantage (EMA). The purpose of this study was to investigate muscle-specific EMA and joint impulse as well as impulse-momentum characteristics of the lifter-barbell system across a range of external loads during the execution of the clean. Collegiate-level weightlifters performed submaximal cleans at 65, 75, and 85% of their 1-repetition maximum (1-RM) while data from a motion analysis system and a force plate were used to calculate lifter-barbell system impulse and velocity, as well as net extensor impulse generated at the hip, knee, and ankle joints and the EMA of the gluteus maximus, hamstrings, quadriceps, and triceps surae muscles. The results indicated that the lifter-barbell system impulse did not change as load increased, whereas the velocity of the lifter-barbell system decreased with greater load. In addition, the net extensor impulse at all joints increased as load increased. The EMA of all muscles did not, however, change as load increased. The load-dependent effects on the impulse-velocity characteristics of the lifter-barbell system may reflect musculoskeletal force-velocity behaviors, and may further indicate that the weightlifting performance is limited by the magnitude of ground reaction force impulse. In turn, the load-dependent effects observed at the joint-level indicated that lifting greater loads were due to greater net extensor impulses generated at the joints of the lower extremity and not greater EMAs of the respective extensor muscles. In combination, these results suggest that lifting greater external loads during the clean is due to the ability to generate large extensor joint impulses, rather than manipulate EMA

Correlational analysis between joint-level kinetics of countermovement jumps and weightlifting derivatives

The purpose of this study was to investigate the mechanical similarity between net joint moments (NJM) of the countermovement jump (CMJ) and the hang power clean (HPC) and jump shrug (JS). Twelve male Lacrosse players performed three maximal effort CMJs and three repetitions of the HPC and JS at 30%, 50%, and 70% of their HPC one repetition maximum (1-RM). Ground reaction forces and motion capture data were used to calculate the NJM of the hip, knee, and ankle joints during each exercise. Statistical comparison of the peak NJM indicated that NJM during the HPC and JS across all loads were equal to or greater than the NJM during the CMJ (all p < 0.025). In addition, correlation analyses indicated that CMJ hip NJM were associated (all p < 0.025) with HPC hip NJM at 30% and 70% (r = 0.611-0.822) and JS hip NJM at 50% and 70% (r = 0.674-0.739), whereas CMJ knee NJM were associated with HPC knee NJM at 70% (r = 0.638) and JS knee NJM at 50% and 70% (r = 0.664-0.732). Further, CMJ ankle NJM were associated with HPC ankle NJM at 30% and 50% (r = 0.615-0.697) and JS ankle NJM at 30%, 50%, and 70% (r = 0.735-0.824). Lastly, knee and ankle NJM during the JS were greater than during the HPC at 30% and 50% of 1-RM (all p < 0.017). The degree of mechanical similarity between the CMJ and the HPC and JS is dependent on the respective load and joint. [Abstract copyright: © Journal of Sports Science and Medicine.

Predicting Net Joint Moments During a Weightlifting Exercise with a Neural Network Model

The purpose of this study was to develop and train a Neural Network (NN) that uses barbell mass and motions to predict hip, knee, and ankle Net Joint Moments (NJM) during a weightlifting exercise. Seven weightlifters performed two cleans at 85% of their competition maximum while ground reaction forces and 3-D motion data were recorded. An inverse dynamics procedure was used to calculate hip, knee, and ankle NJM. Vertical and horizontal barbell motion data were extracted and, along with barbell mass, used as inputs to a NN. The NN was then trained to model the association between the mass and kinematics of the barbell and the calculated NJM for six weightlifters, the data from the remaining weightlifter was then used to test the performance of the NN – this was repeated 7 times with a k-fold cross-validation procedure to assess the NN accuracy. Joint-specific predictions of NJM produced coefficients of determination (r2) that ranged from 0.79 to 0.95, and the percent difference between NN-predicted and inverse dynamics calculated peak NJM ranged between 5% and 16%. The NN was thus able to predict the spatiotemporal patterns and discrete peaks of the three NJM with reasonable accuracy, which suggests that it is feasible to predict lower extremity NJM from the mass and kinematics of the barbell. Future work is needed to determine whether combining a NN model with low cost technology (e.g., digital video and free digitising software) can also be used to predict NJM of weightlifters during field-testing situations, such as practice and competition, with comparable accuracy

Bone health status, muscular performance, aerobic and anaerobic capacities of Malaysian young male state level weightlifting, cycling and squash athletes

This study was carried out to determine the differences in bone health status, muscular performance, aerobic and anaerobic capacities of Malaysian young male state level weightlifting, cycling and squash athletes. Forty four participants (mean age: 17.1 ± 1.6 years old) were divided into sedentary control, weightlifting, cycling and squash groups with 11 participant for each group. Participants’ tibial and radial bone speed of sound (SOS) of dominant and non-dominant arms and legs were measured. In addition, participants’ isokinetic muscular strength and power, hand grip strength, back and leg strength, estimated maximal oxygen uptake (VO2max), and Wingate anaerobic capacities were determined. One way ANOVA was performed for statistical analysis. The present study found that weightlifting, cycling and squash athletes exhibited significantly greater tibial and radial bone SOS (p<0.01) compared to the sedentary control group. Bone SOS of the arm was highest in weightlifting athletes. Meanwhile, bone SOS of the leg was highest in cycling athletes. Weightlifting athletes showed significantly higher values of isokinetic knee extension, shoulder extension and shoulder flexion peak torque (strength) and average power (p<0.05) than cycling and squash athletes. Weightlifting athletes also showed significantly greater hand grip strength (p< 0.001), as well as back and leg strength (p< 0.001) compared to cycling and squash athletes. Cycling and squash athletes showed significantly higher aerobic capacity, i.e. estimated VO2max (p<0.001) compared to weightlifting and squash athletes. Weightlifting athletes exhibited significantly greater peak power (p< 0.05) than cycling and squash athletes. Besides, cycling athletes showed significantly higher anaerobic capacity and power (p< 0.001), and significantly lower fatigue index (p< 0.05) than weightlifting and squash athletes. Weightlifting and cycling athletes showed significantly shorter time to reach peak power (p< 0.01) than squash athletes. The present study findings implying that bone health status and physiological profiles of the athletes are dependent on sport events they were involved in. It is hoped that the results of the present study can be applied and help to facilitate the development of specific training programmes for achieving optimal performance of weightlifting, cycling and squash athletes, as well as promoting healthy lifestyle by engaging in sports like weightlifting, cycling and squash sports

The effect of training with weightlifting catching or pulling derivatives on squat jump and countermovement jump force–time adaptations

The purpose of this study was to examine the changes in squat jump (SJ) and countermovement jump (CMJ) force−time curve characteristics following 10 weeks of training with either load-matched weightlifting catching (CATCH) or pulling derivatives (PULL) or pulling derivatives that included force- and velocity-specific loading (OL). Twenty-five resistance-trained men were randomly assigned to the CATCH, PULL, or OL groups. Participants completed a 10 week, group-specific training program. SJ and CMJ height, propulsion mean force, and propulsion time were compared at baseline and after 3, 7, and 10 weeks. In addition, time-normalized SJ and CMJ force−time curves were compared between baseline and after 10 weeks. No between-group differences were present for any of the examined variables, and only trivial to small changes existed within each group. The greatest improvements in SJ and CMJ height were produced by the OL and PULL groups, respectively, while only trivial changes were present for the CATCH group. These changes were underpinned by greater propulsion forces and reduced propulsion times. The OL group displayed significantly greater relative force during the SJ and CMJ compared to the PULL and CATCH groups, respectively. Training with weightlifting pulling derivatives may produce greater vertical jump adaptations compared to training with catching derivatives

Predicting Muscularity-Related Behavior, Emotions, and Cognitions in Men: The Role of Psychological Need Thwarting, Drive for Muscularity, and Mesomorphic Internalization

We examine the relationships that internalization, need thwarting (NT), and drive for muscularity (DFM), along with their interactions, had with weightlifting, muscle dissatisfaction (MD), and muscle-related-worry (MRW). A sample of 552 men (MAGE = 20.5 years, SD = 3.1) completed the Psychological Need Thwarting Scale, the Internalization subscale of the male version of the Sociocultural Attitudes Towards Appearance Questionnaire, the Drive for Muscularity Scale-Attitudes subscale, the Male Body Attitudes Scale-Muscularity subscale, the Body Change Inventory-Worry subscale, and an inventory assessing weightlifting behavior. DFM significantly predicted weightlifting, MRW, and MD. Internalization significantly predicted weightlifting and MRW. NT significantly predicted weightlifting and MD, and its relationship with MRW approached significance. The interaction terms did not predict weightlifting or MRW. The NT/DFM and NT/Internalization interaction terms predicted MD. These results highlight the role of NT in predicting appearance variables in men

Barbell Trajectory and Kinematics during Two International Weightlifting Championships

Several methods have been used in the scientific literature to study the weightlifting pull. Broadly, these methods are used to measure kinematic or kinetic variables exhibited by the lifter, the barbell, or the lifter-barbell system. However, there is an apparent disconnect between weightlifting research and coaching practice that may reduce the perceived benefits of technique analysis among coaches and present some challenges for coaches who seek to incorporate technique analysis into their coaching practice. Differences and trends in the technique of competitive weightlifting performances are apparent from the available literature. However, there are also gaps in the literature due to infrequent analyses that are limited to narrow subgroups of the weightlifting population. Therefore, the purposes of this dissertation were to 1) update to the scientific knowledge of weightlifting technique and performance, 2) improve coaches’ ability to conduct and interpret technique analysis, and 3) enhance transferability of weightlifting in training to improve sport performance. A review of methods used to evaluate the weightlifting pull provides some practical guidance for coaches on the application and interpretation of weightlifting technique analysis. Video analysis is recommended as the most practicable method for coaches to implement technique analysis themselves. Methods used to study 319 lifts by women and men from two major international competitions demonstrate the feasibility and usefulness of video analysis as an inexpensive, time-efficient, and user-friendly method for coaches to conduct reliable technique analysis. The results of this dissertation suggest that a variety of techniques can be used to achieve international weightlifting success and provide some evidence of changes in weightlifting technique since at least the mid-1980’s. These results also indicate that a stereotypical technique profile among elite international weightlifters does not exist, which further support the notion that strength is a primary determinant of weightlifting ability

The epidemiology of injuries across the weight-training sports

Background: Weight-training sports, including weightlifting, powerlifting, bodybuilding, strongman, Highland Games, and CrossFit, are weight-training sports that have separate divisions for males and females of a variety of ages, competitive standards, and bodyweight classes. These sports may be considered dangerous because of the heavy loads commonly used in training and competition. Objectives: Our objective was to systematically review the injury epidemiology of these weight-training sports, and, where possible, gain some insight into whether this may be affected by age, sex, competitive standard, and bodyweight class. Methods: We performed an electronic search using PubMed, SPORTDiscus, CINAHL, and Embase for injury epidemiology studies involving competitive athletes in these weight-training sports. Eligible studies included peer-reviewed journal articles only, with no limit placed on date or language of publication. We assessed the risk of bias in all studies using an adaption of the musculoskeletal injury review method. Results: Only five of the 20 eligible studies had a risk of bias score ≥75 %, meaning the risk of bias in these five studies was considered low. While 14 of the studies had sample sizes >100 participants, only four studies utilized a prospective design. Bodybuilding had the lowest injury rates (0.12–0.7 injuries per lifter per year; 0.24–1 injury per 1000 h), with strongman (4.5–6.1 injuries per 1000 h) and Highland Games (7.5 injuries per 1000 h) reporting the highest rates. The shoulder, lower back, knee, elbow, and wrist/hand were generally the most commonly injured anatomical locations; strains, tendinitis, and sprains were the most common injury type. Very few significant differences in any of the injury outcomes were observed as a function of age, sex, competitive standard, or bodyweight class. Conclusion: While the majority of the research we reviewed utilized retrospective designs, the weight-training sports appear to have relatively low rates of injury compared with common team sports. Future weight-training sport injury epidemiology research needs to be improved, particularly in terms of the use of prospective designs, diagnosis of injury, and changes in risk exposure

Creating a corporate anti-doping culture: Understanding the role of sport governing bodies

The World Anti-Doping Agency’s (WADA) vision to promote a new moral order in sport and new forms of organisation and management through the World Anti Doping code (WADC) amount to creating a new corporate culture. WADC’s emphasis on policy implementation places sport governing bodies (SGB) and managers at the heart of the enterprise. This represents a double challenge: (i) to the organisational culture of SGBs as it entails creating shared systems of meaning that are accepted, internalised, and acted on at every level of an organization, and (ii) to the IOC and the WADA in regard to universality and particularity, where the general organisational difficulty is how they are to operate at a global (universal) level whilst such apparently intractable differences exist at the particular (local) level. This paper employs Morgan’s (1997) metaphor of organisations as cultures to develop an understanding of the process of endorsing a global anti-doping policy. It explores the enactment of the WADC using the Bulgarian Weightlifting Federation as a case in point. While a good level of universal approval of WADC has been achieved the main issue remains how to get SGBs practices in line with it