Biomechanical Adaptations and Performance Indicators in Short Trail Running

Abstract

Our aims were to measure anthropometric and oxygen uptake ( O 2 ) variables in the laboratory, to measure kinetic and stride characteristics during a trail running time trial, and then analyse the data for correlations with trail running performance. Runners (13 men, 4 women: mean age: 29 ± 5 years; stature: 179.5 ± 0.8 cm; body mass: 69.1 ± 7.4 kg) performed laboratory tests to determine O 2 max , running economy (RE), and anthropometric characteristics. On a separate day they performed an outdoor trail running time trial (two 3.5 km laps, total climb: 486 m) while we collected kinetic and time data. Comparing lap 2 with lap 1 (19:40 ± 1:57 min vs. 21:08 ± 2:09 min, P < 0.001), runners lost most time on the uphill sections and least on technical downhills (-2.5 ± 9.1 s). Inter-individual performance varied most for the downhills (CV > 25%) and least on flat terrain (CV < 10%). Overall stride cycle and ground contact time (GCT) were shorter in downhill than uphill sections (0.64 ± 0.03 vs. 0.84 ± 0.09 s; 0.26 ± 0.03 vs. 0.46 ± 0.90 s, both P < 0.001). Force impulse was greatest on uphill (248 ± 46 vs. 175 ± 24 Ns, P < 0.001) and related to GCT ( r = 0.904, P < 0.001). Peak force was greater during downhill than during uphill running (1106 ± 135 vs. 959 ± 104 N, P < 0.01). Performance was related to absolute and relative O 2 max ( P < 0.01), vertical uphill treadmill speed ( P < 0.001) and fat percent ( P < 0.01). Running uphill involved the greatest impulse per step due to longer GCT while downhill running generated the highest peak forces. O 2 max , vertical running speed and fat percent are important predictors for trail running performance. Performance between runners varied the most on downhills throughout the course, while pacing resembled a reversed J pattern. Future studies should focus on longer competition distances to verify these findings and with application of measures of 3D kinematics.

Ultra Trail Performance is Differently Predicted by Endurance Variables in Men and Women

“…relation with performance of V VT1 and VO 2 peak was larger among women; whereas the magnitude of the correlation with performance of V peak was larger among men. The significant association found between VO 2 peak and performance coincides with most of previous research in the field [3,[5][6][7], although not all [8]. Besides, our results highlight a large association between race time and V VT1 and V VT2 .…”

“…Previous research has consistently demonstrated the importance of body composition upon trail running performance [3,5,7,29]. Some studies reported an inverse relationship between %FM and race time [3,7,29] whereas others found a positive association between %LBM and performance [5].…”

“…Indeed, controversy remains regarding the importance of running economy (i. e., energy demand for a given velocity of submaximal running) upon trail running performance [11,12], with some authors reporting a correlation to race time [8,13] while others do not [4][5][6]. In addition, the importance of substrate utilization is being increasingly emphasized to predict endurance performance [14,15].…”

“…It is therefore of interest for athletes and coaches to identify those factors that play a critical role in performance in order to improve training strategies and competition results. Previous studies have explored possible factors related with race time in trail running races ranging from 21 km to 75 km [3][4][5][6][7][8]. It remains unclear, however, whether the classical physiological variables of endurance running performance (i. e., maximal oxygen uptake, ventilatory thresholds) [9] hold for longer trail running races (i. e., > 100 km).…”

Health profile of older adults assisted by the Elderly Caregiver Program of Health Care Network of the City of São Paulo

“…(9) Yargic et al, (10) have recently examined the acute variation of molecules (interleukin − IL − 6, IL-15 and Hsp72) with significant effects on glucose and fat metabolism after a long distance trail run. Another recent study (11) described biomechanical characteristics of short distance trail runners and their respective performances. Studies comparing ultra trail runners (UTRs) according to competitive level, if national (UTRs-N) or regional (UTRs-R), are lacking.…”