Acute Effects of Motor Imagery on Performance and Neuromuscular Control in Maximal Drop Jumps

Abstract

Motor imagery (MI) used as mental preparation is known to be effective in enhancing athletic performance. However, data about the efficacy of mental preparation on performance and neuromuscular control of subsequent reactive movements are lacking. The purpose of the present study was to investigate the effects of MI on performance in drop jumps and on leg muscle activities. Fifteen participants performed maximal drop jumps from 26 cm height with and without kinesthetic MI in a randomized order. Ankle and knee angles, EMG of soleus, gastrocnemius, tibialis anterior, vastus medialis, biceps femoris and ground reaction forces were measured. Directly after MI participants showed a 3% (p <0.05) higher performance index (PI = air time/ contact time) compared to control jumps. With regard to neuromuscular control participants showed higher preactivities (PRE = 100 ms before touchdown until touchdown) in soleus (11%, p<0.01) and in gastrocnemius (5%, p<0.05) muscles with MI compared to control jumps without MI. During the short latency response (30–60 ms after touchdown), muscle activities were enhanced in SOL and GAS (9%, p<0.01 and 8%, p<0.05, respectively). No differences were found for tibialis anterior, vastus medialis and biceps femoris. These findings indicate an enhanced neural drive directly after MI resulting in higher activation levels of triceps surae muscles before and shortly after touchdown. However, the effectiveness of using MI as mental preparation to enhance performance in drop jumps seems to be limited.