Fatigue during stretch-shortening cycle exercises. II. Changes in neuromuscular activation patterns of human skeletal muscle.

摘要: Detailed electromyographic (EMG) analysis of primarily triceps brachii muscle was carried out on subjects who performed 100 repeated and exhaustive stretch-shortening cycle (SSC) exercises a special sledge apparatus incorporating force plate. The fatigue contractions were submaximal levels but the before-after comparison included also maximal "drop jumps" as well falls to floor. SSC caused clear reduction in mechanical performance capacity muscles. EMG revealed that integrated (IEMG) increased during course both eccentric concentric phases cycle. However, when IEMG time-normalized, changes nonsignificant. IEMG/force ratio especially phase drops. In drops, there great IEMG. Rectified curves averaged blocks ten successive contractions. This appearance short (SLC), medium (MLC), long (LLC) latency reflex components most early contact platform. effects these individual condition dependent so drops trend for potentiation. floor, which represented highest stretch loads muscles, tendency amplitudes components. results suggest exercise muscular activation processes are reduced phase. Muscle spindles suggested become differentially affected by substances depending load intensity contraction.