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  • Author: Nicola Giovanelli x
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Nicola Giovanelli, Paolo Taboga and Stefano Lazzer

Purpose:

To investigate changes in running mechanics during a 6-h running race.

Methods:

Twelve ultraendurance runners (age 41.9 ± 5.8 y, body mass 68.3 ± 12.6 kg, height 1.72 ± 0.09 m) were asked to run as many 874-m flat loops as possible in 6 h. Running speed, contact time (t c), and aerial time (t a) were measured in the first lap and every 30 ± 2 min during the race. Peak vertical ground-reaction force (F max), stride length (SL), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), vertical stiffness (k vert), and leg stiffness (k leg) were then estimated.

Results:

Mean distance covered by the athletes during the race was 62.9 ± 7.9 km. Compared with the 1st lap, running speed decreased significantly from 4 h 30 min onward (mean –5.6% ± 0.3%, P < .05), while t c increased after 4 h 30 min of running, reaching the maximum difference after 5 h 30 min (+6.1%, P = .015). Conversely, k vert decreased after 4 h, reaching the lowest value after 5 h 30 min (–6.5%, P = .008); t a and F max decreased after 4 h 30 min through to the end of the race (mean –29.2% and –5.1%, respectively, P < .05). Finally, SL decreased significantly (–5.1%, P = .010) during the last hour of the race.

Conclusions:

Most changes occurred after 4 h continuous self-paced running, suggesting a possible time threshold that could affect performance regardless of absolute running speed.

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Stefano Lazzer, Desy Salvadego, Paolo Taboga, Enrico Rejc, Nicola Giovanelli and Pietro E. di Prampero

Purpose:

To investigate the effects of an extreme uphill marathon on the mechanical parameters that are likely to affect the energy cost of running (Cr).

Methods:

Eleven runners (27–59 y) participated in the Etna SuperMarathon (43 km, 0–3063 m above sea level). Anthropometric characteristics, maximal explosive power of the lower limb (P max), and maximal oxygen uptake were determined before the competition. In addition, before and immediately after the race, Cr, contact (t c) and aerial (t a) times, step frequency (f), and running velocity were measured at constant self-selected speed. Then, peak vertical ground-reaction force (F max), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), and vertical (k vert) and leg (k leg) stiffness were calculated.

Results:

A direct relationship between Cr, measured before the race, and race time was shown (r = .61, P < .001). Cr increased significantly at the end of the race by 8.7%. Immediately after the race, the subjects showed significantly lower t a (–58.6%), f (–11.3%), F max (–17.6%), k vert (–45.6%), and k leg (–42.3%) and higher t c (+28.6%), Δz (+52.9%), and ΔL (+44.5%) than before the race. The increase of Cr was associated with a decrement in F max (r = –.45), k vert (r = –.44), and k leg (r = –.51). Finally, an inverse relationship between P max measured before the race and ΔCr during race was found (r = –.52).

Conclusions:

Lower Cr was related with better performance, and athletes characterized by the greater P max showed lower increases in Cr during the race. This suggests that specific power training of the lower limbs may lead to better performance in ultraendurance running competition.

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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.

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Nicola Giovanelli, Paolo Taboga, Enrico Rejc, Bostjan Simunic, Guglielmo Antonutto and Stefano Lazzer

Purpose:

To investigate the effects of an uphill marathon (43 km, 3063-m elevation gain) on running mechanics and neuromuscular fatigue in lower-limb muscles.

Methods:

Maximal mechanical power of lower limbs (MMP), temporal tensiomyographic (TMG) parameters, and muscle-belly displacement (Dm) were determined in the vastus lateralis muscle before and after the competition in 18 runners (age 42.8 ± 9.9 y, body mass 70.1 ± 7.3 kg, maximal oxygen uptake 55.5 ± 7.5 mL · kg−1 · min−1). Contact (tc) and aerial (ta) times, step frequency (f), and running velocity (v) were measured at 3, 14, and 30 km and after the finish line (POST). Peak vertical ground-reaction force (Fmax), vertical displacement of the center of mass (Δz), leg-length change (ΔL), and vertical (kvert) and leg (kleg) stiffness were calculated.

Results:

MMP was inversely related with race time (r = –.56, P = .016), tc (r = –.61, P = .008), and Δz (r = –.57, P = .012) and directly related with Fmax (r = .59, P = .010), ta (r = .48, P = .040), and kvert (r = .51, P = .027). In the fastest subgroup (n = 9) the following parameters were lower in POST (P < .05) than at km 3: ta (–14.1% ± 17.8%), Fmax (–6.2% ± 6.4%), kvert (–17.5% ± 17.2%), and kleg (–11.4% ± 10.9%). The slowest subgroup (n = 9) showed changes (P < .05) at km 30 and POST in Fmax (–5.5% ± 4.9% and –5.3% ± 4.1%), ta (–20.5% ± 16.2% and –21.5% ± 14.4%), tc (5.5% ± 7.5% and 3.2% ± 5.2%), kvert (–14.0% ± 12.8% and –11.8% ± 10.0%), and kleg (–8.9% ± 11.5% and –11.9% ± 12%). TMG temporal parameters decreased in all runners (–27.35% ± 18.0%, P < .001), while Dm increased (24.0% ± 35.0%, P = .005), showing lower-limb stiffness and higher muscle sensibility to the electrical stimulus.

Conclusions:

Greater MMP was related with smaller changes in running mechanics induced by fatigue. Thus, lower-limb power training could improve running performance in uphill marathons.

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Nicola Giovanelli, Lea Biasutti, Desy Salvadego, Hailu K. Alemayehu, Bruno Grassi and Stefano Lazzer

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 (V˙O2) and micromolar changes in deoxygenated hemoglobin (Hb)+myoglobin (Mb) concentrations (Δ[deoxy(Hb+Mb)]) on vastus lateralis with a portable near-infrared spectroscopy. Results: V˙O2peak was lower at POST versus PRE (−23.9% [9.0%]; P < .001). V˙O2peak at POST was lower than V˙O2 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.