Nicola Giovanelli

Effects of an Uphill Marathon on Running Mechanics and Lower-Limb Muscle Fatigue.

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.

Factors affecting metabolic cost of transport during a multi-stage running race

The aim of this study was to investigate: (1) the role of , the fraction of (F) and the metabolic cost of transport (CoT) in determining performance during an ultra-endurance competition and (2) the effects of the race on several biomechanical and morphological parameters of the lower limbs that are likely to affect CoT. Eleven runners (aged 29–54 years) participated in an ultra-endurance competition consisting of three running stages of 25, 55 and 13 km on three consecutive days. Anthropometric characteristics, body composition, morphological properties of the gastrocnemius medialis, maximal explosive power of the lower limb and were determined before the competition. In addition, biomechanics of running and CoT were determined, before and immediately after each running stage. Performance was directly proportional to (r=0.77) and F (r=0.36), and inversely proportional to CoT (r=−0.30). Low CoT values were significantly related to high maximal power of the lower limbs (r=−0.74) and vertical stiffness (r=−0.65) and low footprint index (FPI, r=0.70), step frequency (r=0.62) and external work (r=0.60). About 50% of the increase in CoT during the stages of the competition was accounted for by changes in FPI, which represents a global evaluation of medio-lateral displacement of the foot during the whole stance phase, which in turn is associated with the myotendinous characteristics of the lower limb. Thus, lower CoT values were related to greater muscular power and lower FPI, suggesting that a better ankle stability is likely to achieve better performance in an ultra-endurance running competition.

Energetics of vertical kilometer foot races; is steeper cheaper?

Vertical kilometer foot races consist of a 1,000-m elevation gain in <5,000 m of overall distance, and the inclines of the fastest courses are ∼30°. Previous uphill locomotion studies have focused on much shallower angles. We aimed to quantify the metabolic costs of walking and running on very steep angles and to biomechanically distinguish walking from running. Fifteen runners (10 male, 5 female, 32.9 ± 7.5 yr, 1.75 ± 0.09 m, 64.3 ± 9.1 kg) walked and ran for 5 min at seven different angles (9.4, 15.8, 20.4, 24.8, 30.0, 35.0, and 39.2°) all at a fixed vertical velocity (0.35 m/s). We measured the metabolic rates and calculated the vertical costs of walking (Cwvert) and running (Crvert). Using video analysis, we determined stride frequency, stride length, and duty factor (fraction of stride that each foot is in ground contact). At all angles other than 9.4°, Cwvert was cheaper than Crvert (average -8.45 ± 1.05%; P < 0.001). Further, broad minima for both Cwvert and Crvert existed between 20.4 and 35.0° (average Cwvert 44.17 ± 0.41 J·kg(-1)·m(-1) and average Crvert 48.46 ± 0.35 J·kg(-1)·m(-1)). At all angles and speeds tested, both walking and running involved having at least one foot on the ground at all times. However, in walking, stride frequency and stride length were ∼28% slower and longer, respectively, than in running. In conclusion, we found that there is a range of angles for which energy expenditure is minimized. At the vertical velocity tested, on inclines steeper than 15.8°, athletes can reduce their energy expenditure by walking rather than running.

Effects of the Etna Uphill Ultramarathon on Energy Cost and Mechanics of Running

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 (Pmax), and maximal oxygen uptake were determined before the competition. In addition, before and immediately after the race, Cr, contact (tc) and aerial (ta) times, step frequency (f), and running velocity were measured at constant self-selected speed. Then, peak vertical ground-reaction force (Fmax), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), and vertical (kvert) and leg (kleg) 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 ta (-58.6%), f (-11.3%), Fmax (-17.6%), kvert (-45.6%), and kleg (-42.3%) and higher tc (+28.6%), Δz (+52.9%), and ΔL (+44.5%) than before the race. The increase of Cr was associated with a decrement in Fmax (r=-.45), kvert (r=-.44), and kleg (r=-.51). Finally, an inverse relationship between Pmax 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 Pmax 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.

Changes in cardiac and muscle biomarkers following an uphill-only marathon

ABSTRACT The aim of the study was to evaluate changes in cardiac troponin I levels (cTnI) and the main biomarkers of skeletal muscle damage after an uphill-only marathon, along with its relationship with athletes’ physiological parameters. Twenty-two runners participated in the “Supermaratona dell’Etna” (43 km, 0–2850 m AMSL). Before and immediately after the race, body mass and hydration status were measured together with blood sampling. At the end of the race, mean cTnI increased significantly in all athletes (mean +900%), and in 52% of them the cTnI values were over the normal range. Mean creatinine and cortisol increased significantly (by 30.5% and 291.4%), while C-reactive protein levels did not change significantly. Then, an uphill-only marathon showed a significant increase in cardiac and skeletal muscle blood biomarkers of injury, and cTnI levels were not significantly correlated with age, body mass index, V̇O2max, training status, ultra-endurance training experience, race time and blood parameters.

Changes in Running Mechanics During a Six Hours Running Race.

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 (tc), and aerial time (ta) were measured in the first lap and every 30 ± 2 min during the race. Peak vertical ground-reaction force (Fmax), stride length (SL), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), vertical stiffness (kvert), and leg stiffness (kleg) 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 tc increased after 4 h 30 min of running, reaching the maximum difference after 5 h 30 min (+6.1%, P = .015). Conversely, kvert decreased after 4 h, reaching the lowest value after 5 h 30 min (-6.5%, P = .008); ta and Fmax 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.

Effects of strength, explosive and plyometric training on energy cost of running in ultra-endurance athletes

Abstract The aim of the present study was to evaluate the effects of a 12-week home-based strength, explosive and plyometric (SEP) training on the cost of running (Cr) in well-trained ultra-marathoners and to assess the main mechanical parameters affecting changes in Cr. Twenty-five male runners (38.2 ± 7.1 years; body mass index: 23.0 ± 1.1 kg·m−2; V˙O2max: 55.4 ± 4.0 mlO2·kg−1·min−1) were divided into an exercise (EG = 13) and control group (CG = 12). Before and after a 12-week SEP training, Cr, spring-mass model parameters at four speeds (8, 10, 12, 14 km·h−1) were calculated and maximal muscle power (MMP) of the lower limbs was measured. In EG, Cr decreased significantly (p < .05) at all tested running speeds (−6.4 ± 6.5% at 8 km·h−1; −3.5 ± 5.3% at 10 km·h−1; −4.0 ± 5.5% at 12 km·h−1; −3.2 ± 4.5% at 14 km·h−1), contact time (tc) increased at 8, 10 and 12 km·h−1 by mean +4.4 ± 0.1% and ta decreased by −25.6 ± 0.1% at 8 km·h−1 (p < .05). Further, inverse relationships between changes in Cr and MMP at 10 (p = .013; r = −0.67) and 12 km·h−1 (p < .001; r = −0.86) were shown. Conversely, no differences were detected in the CG in any of the studied parameters. Thus, 12-week SEP training programme lower the Cr in well-trained ultra-marathoners at submaximal speeds. Increased tc and an inverse relationship between changes in Cr and changes in MMP could be in part explain the decreased Cr. Thus, adding at least three sessions per week of SEP exercises in the normal endurance-training programme may decrease the Cr.

Short-Term Effects of Rolling Massage on Energy Cost of Running and Power of the Lower Limbs

PURPOSE Self-myofascial release (SMFR) is a type of self-massage that is becoming popular among athletes. However, SMFRs 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.

Design and Implementation of a Low-Cost Mechatronic Shoe for Biomechanical Analysis of the Human Locomotion

In this paper the development of a low-cost and easy wearable mechatronic system for the measurement of ground reaction forces (GRF) for the biomechanical analysis of the human locomotion is presented. The system consists of an insole, a conditioning device for the signals produced by the sensors applied to the insole and a data acquisition system connected to a USB portable storage. The sensors applied to the insole can measure the reaction forces in the horizontal and vertical directions during locomotion. The prototype was validated by comparing the data from the sensors with the values obtained using a force platform.