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.

Impact of EPOC adjustment on estimation of energy expenditure using activity monitors.

PURPOSE: To examine the accuracy of activity monitors in estimating energy expenditure (EE) during activities of varying mode and intensity and to evaluate the impact of including energy expended during recovery from activity (EPOC) on the EE estimate. EE estimates obtained from the Fitbit Surge (FBS), Garmin Vívofit (GV) and SenseWear Armband Mini (SWA) were compared to criterion EE with and without EPOC adjustments during moderate- and vigorous-intensity treadmill and cycling activities. METHODS: Participants (N = 34; 23 males) completed counterbalanced treadmill or cycling conditions, comprised of a resting metabolic rate measurement, 10-min bouts of moderate- and vigorous-intensity activity and an EPOC measurement. Participants simultaneously wore the three activity monitors and a portable metabolic analyser. RESULTS: The FBS provided lowest percent error (PE) during treadmill walking (4.4%) and the GV during moderate (6.4%) and vigorous (-0.1%) cycling bouts. EPOC-adjusted PE was higher than non-EPOC PE across all monitors and activities. Mean absolute error rate (MAPE), indicating overall measurement error, was the smallest for the FBS (14.1%) during moderate treadmill walking and the largest for the SWA (53.5%) for vigorous intensity cycling. Only the FBS had comparable non-EPOC (14.6%) and EPOC-adjusted (17.6%) MAPE during treadmill walking. CONCLUSION: The activity monitors tended to underestimate EE during moderate and vigorous treadmill and cycling activities. The EE estimates from the activity monitors did not account for the energy cost met by anaerobic means during activity, as suggested by the higher EPOC-adjusted EE error rates.

Comparison of Running Economy Values While Wearing No Shoes, Minimal Shoes, and Normal Running Shoes.

Cochrum, RG, Connors, RT, Coons, JM, Fuller, DK, Morgan, DW, and Caputo, JL. Comparison of running economy values while wearing no shoes, minimal shoes, and normal running shoes. J Strength Cond Res 31(3): 595-601, 2017-The purpose of this study was to quantify differences in running economy (RE) at 50 and 70% of each subject's velocity at V[Combining Dot Above]O2max (vV[Combining Dot Above]O2max) across barefoot and 2 mass, stack height, and heel-to-toe-drop controlled footwear conditions (minimal shoes and normal running shoes) in 9 recreational distance runners (mean age 26.8 ± 6.8 years). Over 3 days, subjects ran in one of the footwear conditions while RE (oxygen consumption) and step frequency were measured at each speed with a 5-minute rest between each trial. A 2-way repeated-measures multivariate analysis of variance (p ≤ 0.05) and Bonferroni-adjusted follow-up analyses revealed that RE was not significantly different across footwear conditions at either speed. However, those running barefoot exhibited a higher step frequency than when running in minimal (50%, p = 0.007; and 70%, p < 0.001) and standard footwear conditions (70% only, p < 0.001). Higher step frequencies were also exhibited by those running in minimal versus standard footwear (70% only, p = 0.007). Thus, RE is not affected by footwear or running barefoot in those with experience running in minimal-type footwear. Significant adjustments in step frequency when alternative footwear was introduced may help explain why RE was statistically maintained during each footwear and speed condition across but not between subjects. Therefore, determination of footwear for the enhancement of RE should be based on individual physical characteristics and preferences rather than a global recommendation of an economical running shoe.

School Day Energy Expenditure in Elementary School Children.

BACKGROUND: The purpose was to characterize energy expenditure (EE) during academic subjects and activities during an elementary school day. METHODS: Children in 2nd to 4th grades (N = 33) wore the SenseWear Armband (SWA) for 5 school days to measure EE. Teachers' logs were compared with SWA data to extract information about EE throughout the day. Energy expenditure was also compared among grades. RESULTS: After controlling for body mass, grade level was not a significant predictor of average daily caloric expenditure, F (2, 17.58) = .29, P = .75, ω(2) = .05. When comparing activities throughout the day, relative rates of EE differed significantly, Wilks' F (7, 23) = 52.2, P = .00, ηp(2) = .94, with PE and recess having higher EE. When academic subjects were compared (math, science, language arts), relative rate of EE was also significantly different, Wilks' F (2, 30) = 4.31, P = .02, ηp(2) = .22. For the full sample, relative rate EE was higher in science than in language arts. CONCLUSIONS: The school day provides opportunity for EE for children. These data support the potential benefit of active instruction in language arts as a method to increase school day EE.

Influence of gait manipulation on running economy in female distance runners.

The aim of this investigation was to determine if gait manipulation influences running economy. Following 30 minutes of accommodation to level treadmill running at 3.35 m·s(-1) and determination of VO2peak, nine female distance runners (age = 23.3 ± 4.2 years; body mass = 57.5 ± 5.2 kg; height = 1.64 ± 0.10 m; body fat = 11.4 ± 2.4 %; VO2peak = 54.9 ± 4.1 ml·kg(-1)·min(-1)) completed two treadmill running sessions. In each session, standing VO2 was measured and subjects ran for 6 minutes at 3.35 m·s(-1) under 4 randomly-selected conditions: a) normal running (NL), b) hands behind back (BK), c) hands on head (HD), and d) running with exaggerated vertical oscillation (VOSC). During the last 2 minutes of each running bout, samples of expired air were analyzed to determine oxygen uptake (VO2). Data obtained by averaging gross VO2 values across sessions indicated that VOSC (51.0 ± 2.5 ml·kg(-1)·min(-1)) and HD (46.1 ± 2.0 ml·kg(-1)·min(-1)) resulted in significantly (p < 0.05) elevated VO2 values compared to BK (43.9 ± 2.4 ml·kg(-1)·min(-1)) and NL (43.4 2.6 ml·kg(-1)·min(-1)). VO2 measured during VOSC was also higher compared to HD. Viewed in concert, these results suggest that specific gait manipulations can produce marked decrements in running economy among trained female distance runners. Key pointsThis investigation demonstrates that specific biomechanical manipulations can produce substantive increases in the oxygen cost (VO2) of submaximal running in female distance runners.The magnitude of increases in VO2 reported in this study raises the intriguing possibility that meaningful improvements in running economy might be achieved by manipulating the gait of distance runners who exhibit specific aspects of running style that deviate markedly from the optimum.

Comparison of direct and indirect measures of walking energy expenditure in children with hemiplegic cerebral palsy.

The purpose of this study was to investigate the use of the heartrate (HR) version of the energy expenditure index (EEIHR) as a proxy for measurement of walking oxygen consumption (VO2) in children with cerebral palsy (CP). Thirteen children (eight males, five females; mean age 11 years 2 months [SD 3 years], age range 6 to 15 years) with hemiplegic CP, participated in this study. The study was conducted over three sessions. During session 1, participants were familiarized with testing procedures and given 5 minutes of treadmill walking practice. In session 2, participants completed three 5-minute walking bouts on the treadmill at 0.67m x s(-1) to familiarize themselves with treadmill locomotion. During the final session participants walked at 0.67, 0.89, and 1.12m x s(-1) for 5 minutes while gross oxygen consumption (gross VO2; walking VO2/speed), net VO2 ([walking VO2-resting VO2]/speed), and EEIHR ([walking HR-resting HR]/speed) were measured during the last 2 minutes of each bout. Correlational analyses indicated no relationship (p>0.05) between measures of gross VO2 and EEIHR at each speed. Although no association was evident between net VO2 and EEIHR at 0.67 and 0.89m x s(-1), a moderate relationship (r=0.64; p<0.05) was present between these variables at 1.12m x s(-1). Examination of individual data revealed that most participants displayed an unmatched pattern of response between net VO2 and EEIHR. Our results suggest that caution should be applied when using EEIHR to estimate walking energy expenditure in children with CP.

Longitudinal stratification of gait economy in young boys and girls: the locomotion energy and growth study.

The purpose of this study was to determine if the relative ordering of locomotor oxygen consumption ( VO(2)) values remains stable as healthy children age. Beginning at age 6 and ending at age 10, VO(2) during level treadmill walking and running was quantified in 15 boys and 18 girls who were tested on an annual basis. Following 30 min of treadmill accommodation to each exercise mode, subjects walked and ran for 5 min at 1.34 m s(-1) and 2.23 m s(-1), respectively. During the last 2 min of each 5-min stage, expired gas samples were collected and analyzed to quantify VO(2). For both walking (W) and running (R), 27% of subjects showed an average yearly change in VO(2) rank order of