Purpose: To evaluate the effects of a trail-running race on muscle oxidative function by measuring pulmonary gas exchange variables and muscle fractional O2 extraction. Methods: Eighteen athletes were evaluated before (PRE) and after (POST) a trail-running competition of 32 or 50 km with 2000 or 3500 m of elevation gain, respectively. During the week before the race, runners performed an incremental uphill running test and an incremental exercise by utilizing a 1-leg knee extension ergometer. The knee extension exercise was repeated after the end of the race. During the knee extension test, the authors measured oxygen uptake () and micromolar changes in deoxygenated hemoglobin (Hb)+myoglobin (Mb) concentrations (Δ[deoxy(Hb+Mb)]) on vastus lateralis with a portable near-infrared spectroscopy. Results: was lower at POST versus PRE (−23.9% [9.0%]; P < .001). at POST was lower than at the same workload at PRE (−8.4% [15.6%]; P < .050). Peak power output and time to exhaustion decreased at POST by −23.7% (14.3%) and −18.3% (11.3%), respectively (P < .005). At POST, the increase of Δ[deoxy(Hb+Mb)] as a function of work rate, from unloaded to peak, was less pronounced (from 20.2% [10.1%] to 64.5% [21.1%] of limb ischemia at PRE to 16.9% [12.7%] to 44.0% [18.9%] at POST). Peak Δ[deoxy(Hb+Mb)] values were lower at POST (by −31.2% [20.5%]; P < .001). Conclusions: Trail running leads to impairment in skeletal muscle oxidative metabolism, possibly related to muscle damage from repeated eccentric contractions. In association with other mechanisms, the impairment of skeletal muscle oxidative metabolism is likely responsible for the reduced exercise capacity and tolerance during and following these races.
Nicola Giovanelli, Lea Biasutti, Desy Salvadego, Hailu K. Alemayehu, Bruno Grassi and Stefano Lazzer
Nicola Giovanelli, Filippo Vaccari, Mirco Floreani, Enrico Rejc, Jasmine Copetti, Marco Garra, Lea Biasutti and Stefano Lazzer
Purpose: Self-myofascial release (SMFR) is a type of self-massage that is becoming popular among athletes. However, SMFR’s effects on running performance have not yet been investigated. The aim of this study was to evaluate the effects of SMFR on the cost of running (Cr). In addition, the authors evaluated the effects of SMFR on lower-limb muscle power. Methods: Cr and lower-limb muscle power during squat jump (SJ) and countermovement jump (CMJ) were measured before (PRE), immediately after (POST), and 3 h after (POST 3h) an SMFR protocol (experimental condition). In the control-condition testing session, the same measurements were performed without undergoing the SMFR protocol. Experimental and control conditions were tested in a randomized order. Results: Cr at POST trended to increase compared with PRE (+6.2% [8.3%], P = .052), whereas at POST 3h, Cr was restored to PRE values (+0.28% [9.5%], P = .950). In the experimental condition, no significant effect of time was observed for maximal power exerted during SJ. By contrast, maximal power exerted during CMJ at POST and at POST 3h was significantly higher than that observed at PRE (+7.9% [6.3%], P = .002 and +10.0% [8.7%], P = .004, respectively). The rate of force development measured during CMJ also increased after SMFR, reaching statistical significance at 200 ms from force onset at POST 3h (+38.9%, P = .024). Conclusions: An acute use of foam rollers for SMFR performed immediately prior to running may negatively affect endurance running performance, but its use should be added before explosive motor performances that include stretch-shortening cycles.