Impact Forces of Plyometric Exercises Performed on Land and in Water

摘要: Lower extremity plyometric exercises are commonly used by athletes to develop explosive speed, strength, and power.3 They involve stretch-shortening cycle activity, where eccentric muscle contraction is quickly followed concentric of the same (or muscles). During phase (prestretch), musculotendinous unit stretched, which stores elastic energy, spindles activate stretch reflex.32 Potach Chu32 suggested that both these mechanisms responsible for increased recruitment, allows force production be maximized during action. Plyometric training can enhance jumping performance22 improve balance neuromuscular control landing.29,30 Plyometric drills may include jumps, hops, bounds, or shock drills, vary in intensity,26 often involves repeated maximum efforts. The activity high forces generated also associated with injuries such as patellar tendinopathy.6,32 Typically, intensity an exercise increases greater ground reaction (GRF), when up down from a higher height, single-leg exercises.7 Consequently, landing impacts, joint forces, rate development (RFD), important factors assessing intensity.8,11,19,20 Only limited number studies have compared intensities range exercises.19,20 The majority sessions take place on land. However, there increasing interest aquatic-based because this environment provides physiological psychological benefits,21 has similar performance effects land-based training,23,25,33 useful rehabilitation injury prevention. gravity reduced water buoyancy body density air.21 percentage weightbearing decreases immersion; individual standing level xiphoid process will bear approximately 28% 35% weight (BW), depending sex.36,38 Percentage increase (walking) speed movement.14,21 Research comparing GRF land mainly focused walking.1,34 impact due slower walking speeds reduction apparent BW.1 Jumping more dynamic, substantial vertical displacements movement limbs above water. controls downward body, thus reducing loading while assisting upward jump. Previous highlighted need research examine kinetics exercises.25 To date, 2 shown double-leg squat jumps land.4,39 guide design programs. aim study was quantify performed