Fatigue-induced Changes in Muscle Mechanical Properties and Neuromuscular Activity in Elite Handball Players Following a Simulated Handball Match

Abstract

The ability to exert high maximal muscle force and large contractile rate of force development (RFD) are of vital importance in modern elite team since it involves a large number of repeated accelerations, sprints, jumps, blocking, in fights and rapid changes in moving directions, i.e. side cutting. Male elite handball players often play ∼50 min in a 60 min match and it is reasonable to assume that the ability to exert maximal force (MVC) and rapid force exertion decreases during match play especially for the leg muscles. PURPOSE: To evaluate the fatigue-induced changes in muscle mechanical properties and neuromuscular activity in response to a simulated handball match to gain information on the specific parameters to target by resistance training in order to potentially increase fatigue resistance. METHODS: Ten male elite handball players (22.8±1.5 yrs, 188.4±2.7 cm, 91.7±3.0) were tested before (PRE) and after (POST) a simulated handball match. Maximum jump height (JH), jump power, center of mass displacement and velocity were assessed during a counter-movement jump (CMJ) using force plate analysis and maximal muscle strength (MVC) and RFD were measured with use of isometric dynamometry with synchronous muscle electromyography recordings (EMG). RESULTS: Both quadriceps (−11%, p<0.01) and hamstring (−10%, p<0.05) MVC decreased from PRE to POST. RFD was impaired at time intervals 0-50, 100, 200 ms and at peak RFD (−16–21 %, p<0.05) for the quadriceps and at 0–100 and 200 ms (−17%, p<0.05) for the hamstrings. Decreased peak EMG amplitude were observed in the VL (−28%, p<0.01) and RF (−5%, p<0.05) together with reduced mean EMG amplitude for both the VL (−30–42%, p<0.05) and RF (−21–40%, p<0.05). Reductions in hamstrings EMG were less pronounced. In the CMJ several parameters decreased POST fatigue; jump height (−5%, p<0.01), work (−7%, p<0.01), RFD (−28%, p<0.01) and velocity (−2-4%, p<0.01) while power, concentric force and duration of the jump remained unchanged. CONCLUSIONS: Match-induced fatigue resulted in impaired muscle mechanical and neuromuscular characteristics, which particularly was manifested as a lowered capacity for rapid muscle force exertion (i.e. reduced RFD). Our data support the notion that decreased neuromuscular activity plays an important role in fatigue.