Determinants of recovery from a 161-km ultramarathon

Abstract

The primary study objective was to identify determinants of short-term recovery from a 161-km ultramarathon. Participants completed 400 m runs at maximum speed before the race and on days 3 and 5 post-race, provided a post-race blood sample for plasma creatine kinase (CK) concentration, and provided lower body muscle pain and soreness ratings (soreness, 10-point scale) and overall muscular fatigue scores (fatigue, 100-point scale) pre-race and for 7 days post-race. Among 72 race finishers, soreness and fatigue had statistically returned to pre-race levels by 5 days post-race; and 400 m times at days 3 and 5 remained 26% (P = 0.001) and 12% (P = 0.01) slower compared with pre-race, respectively. CK best modelled soreness, fatigue and per cent change in post-race 400 m time. Runners with the highest CKs had 1.5 points higher (P < 0.001) soreness and 11.2 points higher (P = 0.006) fatigue than runners with the lowest CKs. For the model of 400 m time, a significant interaction of time with CK (P < 0.001) indicates that higher CKs were linked with a slower rate of return to pre-race 400 m time. Since post-race CK was the main modifiable determinant of recovery following the ultramarathon, appropriate training appears to be the optimal approach to enhance ultramarathon recovery.

A Placebo-Controlled Trial of Riboflavin for Enhancement of Ultramarathon Recovery

“…For the subsample of 8 subjects who performed the pre-race 400-m runs, their times at 10 days after the race were statistically similar to pre-race times, although mean times were still ~5% slower at 10 days after the race. Our prior work at the WSER had also demonstrated that muscle pain and soreness ratings had statistically returned to baseline by post-race day 5, but 400-m run times were not examined in that study beyond post-race day 5 at which time pre-race performance had not been fully recovered [3]. In the present work, we extended the post-race time period of examination to 10 days and found that this appears to be close to the timeframe of 400-m run recovery.…”

“…This approach has been previously used at the WSER [2–7] and elsewhere [39], and the values have been found to correlate with plasma CK concentrations [3–5]. Ratings were provided at race registration, during the race at the 48-, 90-, and 126-km checkpoints, at the finish prior to the blood draw, and each morning of the 10 days following the race after being up and moving around for approximately 30 min.…”

“…A 400-m run at maximal speed was used as a functional measurement, which we have previously used successfully [2, 3]. Those subjects enrolled in advance of race registration were asked to perform this test twice on separate days during the 21 days before the race, and all subjects were asked to perform the test on days 3, 5, and 10 after the race.…”

“…Using a level of significance of p  < 0.05, an expected common SD of 1.5 points, and 80% power, the predicted minimum sample size to determine a meaningful group difference of 1.5 points was 13 per group. Recent research at the WSER has shown attrition rate to be roughly 25–30% [2, 3, 40], so we aimed to recruit a minimum of 17 subjects per group.…”

“…The study was performed in association with the 161-km Western States Endurance Run (WSER) since this race is known to induce considerable muscle damage and pain [2, 3, 5–7, 28–32]. Based upon the evidence that riboflavin can protect tissue from oxidative damage and is important in cell repair, we hypothesized that riboflavin would be effective at reducing muscle pain and soreness and improving muscle recovery after this extreme level of exercise.…”