EMG activities and plantar pressures during ski jumping take-off on three different sized hills

Different profiles of ski jumping hills have been assumed to make the initi ation of take-off difficult especially when moving from one hill to another . Neuromuscular adaptation of ski jumpers to the different jumping hills wa s examined by measuring muscle activation and plantar pressure of the prima ry take-off muscles on three different sized hills. Two young ski jumpers v olunteered as subjects and they performed several trials from each hill (K- 35 m, K-65 m and K-90 m) with the same electromyographic (EMG) electrode an d insole pressure transducer set-up. The results showed that the difference s in plantar pressure and EMGs between the jumping hills were smaller than expected for both jumpers. The small changes in EMG amplitudes between the hills support the assumption that the take-off was performed with the same intensity on different jumping hills and the timing of the gluteus EMG demo nstrates well the similarity of the muscle activation on different hills. O n the basis of the results obtained it seems that ski jumping training on s mall hills does not disturb the movement patterns for bigger hills and can also be helpful for special take-off training with low speed. (C) 2001 Else vier Science Ltd. All rights reserved.