Muscle Fascicle Behavior during Eccentric Cycling and Its Relation to Muscle Soreness

作者：Penailillo Luis^*; Blazevich Anthony J; Nosaka Kazunori

来源：Medicine and Science in Sports and Exercise, 2015, 47(4): 708-717.

DOI：10.1249/MSS.0000000000000473

• LENGTHENING CONTRACTIONS
• FASCICLE LENGTH
• MUSCLE-TENDON BEHAVIOR
• DELAYED ONSET MUSCLE SORENESS
• TENDINOUS TISSUE
• REPEATED BOUT EFFECT

A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. Purpose This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect.
Methods Eleven untrained men (27.1 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling.
Results Soreness was greater (P < 0.0001) after ECC1 than ECC2, although MVC changes were not different between bouts (P = 0.47). No significant differences in peak EMG amplitude (normalized to EMG during MVC), crank peak torque, or knee angles were evident between bouts. However, fascicle elongation was 16% less during ECC2 than ECC1 (P < 0.01), indicating less fascicle strain in ECC2. Maximum TT length occurred at a smaller knee joint angle during ECC2 than ECC1 (P = 0.055).
Conclusion These results suggest that a lesser fascicle elongation and earlier TT elongation were associated with reduced muscle soreness after ECC2 than ECC1; thus, changes in muscle-tendon behavior may be an important mechanism underpinning the protective effect.

• 出版日期2015-4