A randomized controlled trial: effectiveness of 10-week Nordic Hamstring exercise training and subsequent detraining in healthy young men

Abstract

Purpose: Nordic Hamstring Exercise (NHE) is used to increase hamstring muscle strength, prevent injuries. We aimed to reveal the acute, long-term effects of NHE, followed by detraining on demographic measurements, flexibility, anaerobic power, damage, fatigue, oxidative stress, blood lactate levels. Material and method: A total of 40 sedentary healthy male participated the experiments. 20 of them underwent 10 weeks of progressive NHE followed by detraining. Muscle architecture was determined by ultrasonography, strain ratio by elastography. Anaerobic power was assessed by standing long jump, vertical jump, flexibility by sit reach tests. Creatine kinase activity, oxidant/antioxidant parameters were measured by commercial kits. Results: NHE allowed subjects to lose weight, which was reversed by detraining of 5 weeks. Exercise caused an increase in knee angles that wasn’t affected by detraining. 10-week NHE caused a partially reversed increase in anaerobic performance upon detraining. NHE resulted in increment of biceps femoris long head area, pennation angle which were reversed by detraining of 10-weeks. Blood lactate, muscle pain, fatigue were increased after each exercise session. NHE didn’t change oxidative stress but, 5-week detraining resulted in an increase in total oxidant capacity, oxidative stress index. Detraining of 10 weeks caused a reduction of these parameters. Conclusions: It has been observed that most of the gains obtained with 10-week progressive NHE are reversed with 5-week detraining. These results may guide the selection of the exercise type to increase performance and muscle strength.