Repeated Bout Effect of Downhill Running on Physiological Markers of Effort and Post Exercise Perception of Soreness in Trained Female Distance Runners.

This study examined the effect of repeated bouts of level and downhill running on physiological markers of effort and exercise-induced muscle soreness in trained female distance runners. Ten participants (Age: 24.4 ± 2.0 years; V̇O 2peak : 52.9 ± 1.1 mL·kg -1 ·min -1 ), naïve to downhill running, completed six alternate 5 min trials of level and downhill running (-15%) at a 70% velocity at V̇O 2peak on two occasions, three weeks apart. Perceived muscle soreness was measured upon completion and in the 72 h post exercise. V̇O 2 , Heart Rate (HR), Blood Lactate (BLa), and Respiratory Exchange Ratio (RER) were lower running downhill ( p < 0.016, ηp 2 > 0.541). For the first downhill run, Rating of Perceived Exertion (RPE) was higher compared to that for level running ( p = 0.051; d = 0.447), but for the remaining trials, RPE was lower when running downhill ( p < 0.004; d > 0.745). V̇O 2 , HR, and RER were not different in the second bout ( p > 0.070, ηp 2 < 0.318); however, V̇O 2 was lower in each downhill trial (Δ = 1.6-2.2 mL·kg -1 ·min -1 ; d = 0.382-0.426). In the second bout, BLa was lower ( p = 0.005, ηp 2 = 0.602), RPE in the first trial was lower ( p = 0.002; d = 0.923), and post exercise perceived soreness of the gastrocnemius, quadriceps, and hamstrings was attenuated ( p < 0.002; ηp 2 > 0.693). Perceived soreness of the gluteal muscles was lower in the second bout immediately post exercise, 24 h, and 48 h post exercise ( p < 0.025; d > 0.922). A repeated bout of downhill running attenuated perceived muscle soreness and may modulate the physiological and perceived physical demand of a second bout of level and downhill running.