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BACKGROUND: Portable metabolic carts are a popular tool to assess aerobic capacity and affirm many cardiorespiratory conditions. They may also measure strength training performance. Given their popularity and increased usage to assess strength training performance; their data accuracy and consistency are important to determine. OBJECTIVE: Measure Cosmed K4 b2 portable metabolic cart data repeatability from consecutive seated calf press workouts. METHODS: Fifteen women and twelve men did two workouts that began with a stationary cycling warm-up followed by calf presses. Gases were measured before the calf press portion of workouts to establish baseline VO2 and VCO2 values, as well as continually throughout and after the calf press protocol. Subjects were detached from the cart once gas values returned to baseline after workouts concluded. In addition to VO2 and VCO2, repeatability was quantified for: breaths per minute, tidal volume, ventilation, O2 uptake relative to body mass, expired O2 and CO2 fractions, percent fat and carbohydrate utilization, METS and total energy cost. Mean and peak values per variable were analyzed. Repeatability was assessed separately for male and female data, as well as with values pooled, by the following: intraclass correlation coefficients, eta squared, limits of agreement, coefficient of variation and smallest real difference percent. RESULTS: Per variable, repeatability values across workouts were low. Female intraclass correlation coefficient mean values were more repeatable for variables related to gas measurements, yet male data were generally more repeatable for those related to substrate usage. CONCLUSIONS: Results for some repeatability indices were influenced by measurement magnitude. Peak values were predictably less repeatable than those for mean values. Most smallest real differences percent scores are so high they were rendered irrelevant or meaningless to determine true differences among paired values. Results suggest low data repeatability that are likely appropriate and realistic for the exercise protocol, hardware and intensity examined.

BACKGROUND: Ultrasound is an important tool to diagnose many clinical conditions. Yet hand-held devices may be prone to more data variability in part from the greater likelihood of human error. OBJECTIVE: Quantify intra-rater reliability of subcutaneous skin fold thickness from a hand-held ultrasound device. PARTICIPANTS: College-age subjects (18 men, 14 women) submitted to two sets of ultrasound subcutaneous skin fold measurements spaced (mean + sem) 10.6 + 2.2 days apart. Per measurement, they stood relaxed as ultrasound measured the subcutaneous skin fold thickness that covered their left leg’s calf muscle group. Measurements occurred with a hand-held device (BodyMetrix Pro System BX2000; Livermore, CA) used in accordance with the manufacturer’s guidelines. Four subcutaneous measurements were made 90∘ apart (anterior, medial, posterior, lateral) at the portion of the left calf with the largest circumference. To assess intra-rater reliability, we used intraclass correlation coefficients, limits of agreement, coefficient of variation and the smallest real difference. RESULTS: Intra-rater reliability was high for most of our statistical tests. CONCLUSION: Despite the relatively long period between measurements, our hand-held ultrasound device exhibited a high degree of intra-rater reliability. Given our results, ultrasound measurements may be a useful tool to quantify skin fold thickness.

Gray, WD, Jett, DM, Cocco, AR, Vanhoover, AC, Colborn, CE, Pantalos, GM, Stumbo, J, Quesada, PM, and Caruso, JF. Ergogenic and physiological outcomes derived from a novel skin cooling device. J Strength Cond Res 35(2): 391–403, 2021—Our study's purpose assessed a cooling headband's ergogenic and physiological impacts. Subjects (15 women and 13 men) completed six visits; the final 3 entailed rowing workouts with the following treatment conditions: no head cooling (NoHC), intermittent head cooling during exercise (HCex), and intermittent head cooling during exercise and post-exercise recovery (HCex&post). Data collection occurred at the following times (a) pre-exercise and post–warm-up, (b) between stages of up to eight 2-minute bouts, and (c) at 5, 10, 15, and 20 minutes post-exercise. In addition to distance rowed, thermal, cardiovascular, perceptual, and metabolic measurements were obtained. Results included a small yet significant intertreatment difference (HCex, HCex&post > NoHC) for distance rowed. Our cardiovascular and metabolic indices exhibited sex and time differences but likely did not contribute to the ergogenic effect. Yet, left hand temperatures (LHT) exhibited significant 2-way and 3-way interactions that were the likely source of the ergogenic effect. Auditory canal temperature (AUDT) results suggest the head is sensitive to heat increases, yet LHT data show headband use evoked significantly greater temperature increases at the hand's palmar surface, indicative of heat transfer. We conclude, and our practical applications suggest, the headband's ergogenic effect was manifested by cold-induced vasodilation at the hand's palmar surface, rather than heat losses through the head.

BACKGROUND: Global positioning system (GPS) data, when obtained from athletes offers unique information on their performance. Given the information GPS data provides, it is important to identify data most pertinent to an athlete’s performance. OBJECTIVE: We evaluated a GPS-based running quality variable to predict the variance in total player load (TPL) and player load per minute (PLPM) from female soccer player (n= 26) data. METHODS: Running quality was the ratio of the displacement per minute to total distance covered. TPL was quantified as the sum of velocity change rates in all three planes of motion, while PLPM was a ratio of load generated per minute of activity. RESULTS: With a logarithmic transformation of TPL data, a Pearson Product Moment Correlation analysis revealed running quality accounted for significant (r=-0.65) amounts of our criterion’s variance, which implied higher running quality led to lower log (TPL) values. With PLPM as our dependent variable, running quality correlated with significant (r= 0.63) amounts of our criterion’s variance. CONCLUSIONS: Movement efficiency appears to be an important contributor to our correlations. We suggest running quality be examined as a correlate to performance in other sports in which running is crucial to success.