Guasha improves the rating of perceived exertion scale score and reduces heart rate variability in male weightlifters:a randomized controlled trial

OBJECTIVE: To evaluate the effects of Guasha therapy on the rating of perceived exertion(RPE) scale score, and heart rate variability(HRV).METHODS: A randomized controlled trial of Guasha(skin scraping) was compared with a sham scraping group and control group. Sixteen sessions within an 8-week period were completed. Sixty-five male weightlifters who had undergone normal weightlifting training for a mean of 5 years before study commencement were recruited. The RPEscale score of "snatch", "clean and jerk" maneuvers(85% of one-repetition maximum), and HRV were measured before and after the intervention.RESULTS: The RPE scale score for snatch, clean and jerk were reduced significantly after intervention in the Guasha group and sham group. However, there was a significant difference in the low frequency(LF) domain and LF/high frequency(HF) ratio(P <0.05): the LF domain decreased, and the LF/HF ratio decreased.CONCLUSION: Guasha could be used to reduce the RPE scale score, and increase the response to HRV.Guasha could be considered as an alternative to some types of recovery from sports training.

Weightlifting Motion Generation for a Stance Robot with Repeatedly Direct Kinematics

This research focuses on how to control the robot easily and how to generate the better trajectories of the robot with multiple joints to implement weightlifting motion. The purpose of this research is to develop a multijoint robot can stand up successfully with an object. This research requires the operations with two items. First, when the object is lifted up slowly, the robot could stand up as easily as possible and does not tumble down. Second, the load applied on each joint should be as small as possible. In this article, a motion control method is proposed to evaluate the variations of the load torque and rotated angle of each joint with the geometrical constraints in the procedure and find the best algorithm to generate the trajectory of a weightlifting motion by a stance robot with repeatedly direct kinematics.

A Wavelet-Based Method to Predict Muscle Forces From Surface Electromyography Signals in Weightlifting

The purpose of this study was to develop a wavelet-based method to predict muscle forces from surface electromyography （EMG） signals in vivo. The weightlifting motor task was implemented as the case study. EMG signals of biceps brachii, triceps brachii and deltoid muscles were recorded when the subject carried out a standard weightlifting motor task. The wavelet-based algorithm was used to process raw EMG signals and extract features which could be input to the Hill-type muscle force models to predict muscle forces. At the same time, the musculoskeletal model of subject＇s weightlifting motor task was built and simulated using the Computed Muscle Control （CMC） method via a motion capture experiment. The results of CMC were compared with the muscle force predictions by the proposed method. The correlation coefficient between two results was 0.99 （p〈0.01）. However, the proposed method was easier and more efficiency than the CMC method. It has potential to be used clinically to predict muscle forces in vivo.

Effects of Gua Sha therapy on weightlifting training: a randomized trial

OBJECTIVE: To evaluate the effect of Gua Sha therapy on weightlifting training.METHODS: The sample size was calculated by conducting a pilot study. A total of 44 male weightlifters were randomly assigned to either the Gua Sha group(n = 15), sham scraping group(n = 14), or control group(n = 14). The participants in the Gua Sha group and sham scraping group received 16 sessions of Gua Sha therapy during normal weightlifting training for 8 weeks. No treatment was applied to participants in the control group. The effectiveness of Gua Sha therapy was evaluated by measuring weightlifting ability, the rating of perceived exertion(RPE) of snatch and clean and jerk(85% of1 repetition maximum), and creatinine kinase(CK),blood urea nitrogen(BUN), and immunoglobulin A levels.RESULTS: Gua Sha therapy treatment significantly increased weightlifting ability in participants in the Gua Sha group(P < 0.01). The RPE values of snatch and clean and jerk were significantly lower in the Gua Sha group and sham scraping groups compared with the control group(P < 0.05). CK levels were lower and immunoglobulin A levels were significantly higher in the Gua Sha group compared with sham scraping group and control group(both P < 0.05). BUN levels tended to be reduced only in the Gua Sha group. A close correlation between CK levels and the RPE was found in the Gua Sha group.CONCLUSION: Gua Sha therapy can facilitate weightlifting ability, reduce the RPE, and inhibit muscle injury by promoting recovery from fatigue caused by normal weightlifting training. Gua Sha therapy could be an effective treatment to complement normal weightlifting training.

Clark Phenomenon" of Physical Efficiency Sportsmen in Major Competitions

The term "Clark Phenomenon" refers to unexpected failures of topranking ahletes in major competitions.Top athletes in the 21 - 24th Olympic Games and top six athletes in the 1- 6th National Games of the events of track and field, swimming and weightlifting weree investigated in this study. Statistic analysis of their achievements in major competitions showed that the "Clark Phenomenon" appeared in about one third of these top athletes. The incidence of "Clark Phenomenon" of the top six athletes was 0. 8%. Discussion was made on the causes that lead to serious "Clark Phenomenon" of Chinese athletes in the Olympic Games. An Evaluation Standard of Normal Performance in Major Competition for the events of track and field, swimming and weightlifing was established.

Acute Post-Activation Potentiation Effects of Heavy High-Pulls on Clean Performance

Aim The concept of post-activation potentiation(PAP)is still novel from a training perspective and lacks breadth relative to weightlifting exercises.Purpose The purpose of this study was to investigate the acute effects of a conditioning activity(clean high pulls)on the performance of a main activity(clean)after the conditioning activity.Methods Eleven volunteers who engaged in weightlifting(Male=5,Female=6)participated in two different testing ses-sions(experimental vs.control).Baseline measurements were taken following the warm-up.The testing condition was performed and additional measurements were taken at 30 s,2 min,4 min,6 min,8 min,10 min,and 12 min into recovery.A linear position transducer was used to collect peak power,peak velocity,and displacement of the barbell during the clean.Multiple 2×8 repeated measures ANOVAs were used to analyze the data along with a paired samples t test between baseline and"best"values.Results There was no interaction or main effect for condition(P>0.05).However,there was a significant main effect for time(P<0.05)for all variables.The"best"values were significantly(P<0.05)greater than baseline values(peak power:experimental=1354.76 ±521.24 W vs.baseline 1216.03 ±492.30 W;peak velocity:experimental=2.66 ±0.44 m/s vs.baseline 2.50 ±0.44 m/s;displacement:experimental=111.07 ± 12.09 cm vs.baseline 107.01 ± 11.32 cm).Conclusions The findings of this study are in partial agreement with previous literature where the warm-up was probably enough to elicit PAP.Therefore,recommendations for future studies could include utilizing a more elite population and to ensure all potential participants can squat at least 2 x their body weight.