Off-road running continues to grow in popularity, with differing event categories existing, and terminologies are often used interchangeably and without precision. Trail running, mountain running, skyrunning, fell running, orienteering, obstacle course racing and cross-country running all take place predominantly in off-road terrain. Ultramarathon running refers to any running event over marathon distance conducted in any terrain and surface. Although some overlap may exist between these running events, mainly through the common denominator of off-road terrain, distinct features need to be recognised. As scientific interest in these activities grows, it becomes important to clarify these terms and develop a universal language for discussing these events. Similarly, off-road running athletes are generally not properly defined within the scientific literature, which makes intra- and inter-study comparisons difficult. The current position statement of the Ultra Sports Science Foundation highlights the different off-road running events and recommends clear reference to distance, surface, elevation change and altitude, type of event (continuous vs. staged), type of support, name and year of the event, governing body, and guidance on terminology. We further recommend to describe off-road running athletes by basic data, physiological determinants, training and competition characteristics in the scientific literature in order to facilitate and guide further research and practice.

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 (D_m) 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 (t_c) and aerial (t_a) 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 (F_max), vertical displacement of the center of mass (Δz), leg-length change (ΔL), and vertical (k_vert) and leg (k_leg) stiffness were calculated.Results: MMP was inversely related with race time (r = –.56, P = .016), t_c (r = –.61, P = .008), and Δz (r = –.57, P = .012) and directly related with F_max (r = .59, P = .010), t_a (r = .48, P = .040), and k_vert (r = .51, P = .027). In the fastest subgroup (n = 9) the following parameters were lower in POST (P < .05) than at km 3: t_a (–14.1% ± 17.8%), F_max (–6.2% ± 6.4%), k_vert (–17.5% ± 17.2%), and k_leg (–11.4% ± 10.9%). The slowest subgroup (n = 9) showed changes (P < .05) at km 30 and POST in F_max (–5.5% ± 4.9% and –5.3% ± 4.1%), t_a (–20.5% ± 16.2% and –21.5% ± 14.4%), t_c (5.5% ± 7.5% and 3.2% ± 5.2%), k_vert (–14.0% ± 12.8% and –11.8% ± 10.0%), and k_leg (–8.9% ± 11.5% and –11.9% ± 12%). TMG temporal parameters decreased in all runners (–27.35% ± 18.0%, P < .001), while D_m 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.

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 (Cw_vert) and running (Cr_vert). 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°, Cw_vertwas cheaper than Cr_vert(average −8.45 ± 1.05%; P < 0.001). Further, broad minima for both Cw_vertand Cr_vertexisted between 20.4 and 35.0° (average Cw_vert44.17 ± 0.41 J·kg⁻¹·m⁻¹and average Cr_vert48.46 ± 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.

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 (t_c) increased at 8, 10 and 12 km·h⁻¹ by mean +4.4 ± 0.1% and t_a 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 t_c 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.

In recent years, different companies have developed devices that estimate “running power”. The main objective of this paper is to evaluate the effect of running speed on aerobic and running powers measured using force plates and by different devices. The second objective is to evaluate the relationship between aerobic power and running powers measured using force plates and by different devices. We enrolled 11 subjects in the study, they performed 5‐min running trials at 2.22, 2.78, 3.33, 3.89 and 4.44 m/s respectively on a force‐measuring treadmill while we collected metabolic data. We calculated running power as the dot product of ground reaction force and velocity of the centre of mass and compared it to the running power estimates of three devices: Skillrun (Technogym), Stryd Summit Powermeter (Stryd) and Garmin HRM‐Run (Garmin). We found statistically significant linear correlations with running powers measured by all devices and running speed. Although absolute running power measurements were different among devices, an increase of 1 m/s in running speed translated to an increase of 0.944 W/kg in running power (p < 0.001). We found statistically significant linear correlations with running powers measured by all devices and aerobic power, in particular: as aerobic power increases by 1 W/kg, running power increases by 0.218 W/kg for all devices (p < 0.001). For level treadmill running, across speeds, running power measured by commercially available devices reflects force‐based measurements and it can be a valuable metric, providing quasi real‐time feedback during training sessions and competitions.Highlights We evaluated the effect of running speed on aerobic and running powers measured using force plates and by different devices. We also compared the relationship between aerobic power and running powers measured using force plates and by different devices. We found statistically significant linear correlations with running powers measured by all devices and aerobic power, in particular: as aerobic power increases by 1 W/kg, running power increases by 0.218 W/kg for all devices. For level treadmill running, across speeds, running power measured by commercially available devices reflects force‐based measurements and it can be a valuable metric, providing quasi real‐time feedback during training sessions and competitions.

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.