Visual classification of running economy by distance running coaches.

AbstractObjectives: This study assessed the ability of coaches to rank-order distance runners on running economy (RE) through visual assessment. Methods: Running economy was measured in five trained recreational distance runners at a speed of 3.57 m·s-1, with a minimum VO2 difference of 2-mL.kg-1.min-1 between adjacent runners. Following measurement of RE, participants were filmed from the front, side, and rear while running on a treadmill. Endurance coaches from high school to international level (N = 121) viewed each video and ranked the runners on a scale from 1 (most economical) to 5 (least economical). Coaches also completed a demographic questionnaire and listed running style biomechanical observations they used in determining each ranking. A cumulative odds ordinal logistic regression with proportional odds was run to determine the effect of coaching level, years of coaching experience, years of training experience, competition level, certification status, and education level, on the ability of distance running coaching to accurately rank RE among a group of runners. Results: No coaching characteristic was a significant predictor of ranking accuracy, χ2 = 3.566, p = .735. Conclusions: Visual assessment of effort, based on RE, is a difficult task, even for the trained eye and could be related to difficulty in understanding the interaction effect of various RE factors or the translation of scientific-based knowledge to the field of play. Practically, coaches should be cautious when recommending biomechanical adjustments without considering the interconnected factors related to such changes.

The effect of running barefoot and in barefoot-style footwear on running economy at two self-determined speeds.

BACKGROUND: The impact of barefoot running and footwear choice on running economy (RE; steady state oxygen consumption) is heavily debated. Therefore, this study measured RE when running barefoot versus two shod conditions. METHODS: Recreational male runners (N.=8) with experience running in both five-toed minimal (FTMS) and standard cushioned running shoes (SCRS), participated in RE trials while barefoot, FTMS, and SCRS for 5 minutes each trial at both 50% and 70% of speed at maximal oxygen uptake (sVO2max), while RE and step frequency (Sf) were measured. Separate one-way repeated measures ANOVAs were conducted for each footwear condition and each speed, on RE and Sf. RESULTS: No significant differences in RE were found at 50% or 70% sVO2max. Step frequency was significantly different at 70% sVO2max (F(2, 14)=6.74, P=0.009, partial ω2=0.06, as running barefoot (173.00±10.50 steps/min) exhibited a higher Sf than running in FTMS (68.81±10.94 steps/min; P=0.008) or SCRS (166.62±8.42 steps/min; P=0.044) conditions. CONCLUSIONS: No statistical RE benefit was found when running barefoot over FTMS or SCRS, possibly explained by a Sf adaptation at higher speeds. However, practically speaking, when shoe mass is controlled for, footwear choice has a moderate but worthwhile effect on RE. Consequently, formal familiarization and/or training in the FTMS may improve RE when compared to running in SCRS or barefoot in certain individuals.