PRIOR ECCENTRIC EXERCISE REDUCES (V) over dotO2PEAK AND VENTILATORY THRESHOLD BUT DOES NOT ALTER MOVEMENT ECONOMY DURING CYCLING EXERCISE

Black, CD and Dobson, RM. Prior eccentric exercise reduces (V) over dotO(2)peak and ventilatory threshold but does not alter movement economy during cycling exercise. J Strength Cond Res 26(9): 2530-2537, 2012-Exercise-induced muscle damage (EIMD) has been shown to reduce force production and result in delayed-onset soreness and pain in the damaged muscle(s). Cycling in the presence of EIMD reduces peak power output and time-trial performance. However, its effect on peak aerobic capacity has not been widely studied. The purpose of this study was to examine the impact of EIMD targeted specifically to the quadriceps muscle group on peak oxygen consumption ((V) over dotO(2)peak) during cycling. Ten participants (4 men, 6 women) completed a (V) over dotO(2)peak test on a cycle ergometer before and 48 hours after performing 24 eccentric contractions with their right and left quadriceps with a weight equal to 120% of 1-repetition maximal concentric strength (1RM). The EIMD was assessed using 1RM, and muscle soreness was assessed using a 100-mm visual analog scale. The presence of EIMD was confirmed by a 9% reduction in 1RM (p = 0.0001) and increased ratings of soreness from 2.4 +/- 2.1 to 24.6 +/- 10.8 mm (p = 0.001). The (V) over dotO(2)peak was reduced from 46.2 +/- 9.7 to 41.8 +/- 10.7 ml.kg(-1).min(-1) (10%; p = 0.01) with participants terminating exercise at lower heart rates 191 +/- 9 vs. 186 +/- 10 b.min(-1) (p = 0.02) and power output 248 +/- 79 vs. 238 +/- 81 W (p = 0.02) after EIMD. Additionally, ventilatory threshold decreased from 34.2 +/- 7.8 to 30.5 +/- 8.5 ml.kg(-1).min(-1) (11%; p = 0.031). Despite the reduction in (V) over dotO(2)peak, cycling economy (p = 0.17) did not differ pre-EIMD and post-EIMD. These findings indicate that EIMD reduced peak aerobic exercise capacity to an extent that could result in meaningful reductions in exercise performance. The reduction is likely attributable to a combination of reduced strength, earlier accumulation of lactic acid, and heightened muscle pain during exercise.