Increased Rate of Peak Torque Development in Human Skeletal Muscle following Isokinetic Training with Sports Beverages

Objective:The present study examined the effect of isokinetic training with sports beverages on the rate of peak torque development in athlete skeletal muscle during maximal muscle contraction.Methods:Twenty-seven taekwondo athletes in universitiy were randomly divided into four groups,TD group(n=7)with routine professional training and isokinetic exercise with sports beverages,T group(n=6)with routine professional training and isokinetic exercise with water,D group(n=7)with routine professional training and with beverages,C group(n=7)with routine professional training and with water.Experimental session for 10 weeks,included training for 6weeks and detraining 4 weeks.Subjects were asked to complete quadriceps and hamstring muscle isokinetic training in two legs,including 2sets of 7repetitions concentric contraction at 60°/s and 18 repetitions concentric contraction at 180°/s,and 7repetitions eccentric contraction at 20°/s,then 18 repetitions concentric contraction at 180°/s,1-min rest in set,3-min rest interval set,3days a week.Moment of skeletal muscle eccentric contraction was 150% of the maximum moment of resistance in the first 3 weeks,and 220%in last 3weeks.Sports beverages were carbohydrate solution(6% wt/vol)including creatine(0.1g/kg weight),carbohydrate(1g/kg weight)and protein(0.4g/kg weight).Drank 1/3before isokinetic exercise,then 150 ml per 15 minutes until finishing exercise,the remaining solution was drunk up after finishing exercise in TD group and Dgroup.The volume of water was(kg weight)/6% ml.The maximum torque,iEMG and completion time were measured in predominant leg at 60°/s and 180°/s before training,after 6 weeks training and 4 weeks detraining,calculated RFD and RER.Results:(1)RFD and RER of hamstring muscle increased in TD group than D group at 60°/s(P<0.05)after 6 weeks training.RFD and RER of quadriceps were higher in TD group than T,D,C groups at 180°/s(P<0.05)after 6 weeks training and 4weeks detraining.(2)RER of BF increased in TD group than D group while flexing knee at 60°/s(P<0.05)after 6weeks training.RER of VL increased in TD group than C group while extending knee at 180°/s(P<0.05)after 4 weeks detraining.RER of RF increased in TD group than T,D,C groups while extending knee at 180°/s(P<0.05)after 6weeks training and 4weeks detraining.Conclusion:The rate of force(or peak torque)development significantly increased after isokinetic training with sports beverages and detraining,which was associated with increased neuromuscular activity.And BF,RF,VL was suggested to be have a major role in muscle strength formation accounted for their neural activation significantly.