Allometric scaling of Wingate anaerobic power test scores in men

Allometric Scaling Hip Joint Moments Optimally Reduces Anthropometric Differences in Males and Females

Running biomechanics are scaled to reduce the effects of anthropometric differences between participants. Ratio scaling has limitations, and allometric scaling has not been applied to hip joint moments. The aim was to compare raw, ratio and allometrically scaled hip joint moments. Sagittal and frontal plane moments of 84 males and 47 females were calculated while running at 4.0 m/s. Raw data were ratio scaled by body mass (BM), height (HT), leg length (LL) and BM multiplied by HT (BM*HT) and LL (BM*LL). Log-linear (for BM, HT and LL individually) or log-multilinear regression (BM*HT and BM*LL) exponents were calculated. Correlations and r2 values assessed the effectiveness of each scaling method. Eighty-five per cent of raw moments were positively correlated to the anthropometrics with r2 values of 10-19%. In ratio scaling, 26-43% were significantly correlated to the moments and a majority were negative, indicating overcorrections. The most effective scaling procedure was the allometric BM*HT, as the mean shared variance between the hip moment and anthropometrics was 0.1-0.2% across all sexes and moments and none had significant correlations. Allometric scaling of hip joint moments during running are advised if the goal is to remove the underlying effects of anthropometrics across male and female participants.

Evaluation of spinal force normalization techniques

Division normalization is commonly used in biomechanics studies to remove the effect of anthropometric differences (e.g., body weight) on kinetic variables, facilitating comparison across a population. In spine biomechanics, spinal forces are commonly divided by the body weight or the intervertebral load during a standing posture. However, it has been suggested that offset and power curve normalization are more appropriate than division normalization for normalizing kinetic variables such as ground reaction forces during walking and running. The present study investigated, for the first time, the effectiveness of four techniques for normalizing spinal forces to remove the effect of body weight. Spinal forces at all lumbar levels were estimated using a detailed OpenSim musculoskeletal model of the spine for 11 scaled models (50-100 kg) and during 13 trunk flexion tasks. Pearson correlations of raw and normalized forces against body weight were used to assess the effectiveness of each normalization technique. Body weight and standing division normalization could only successfully normalize L₄L₅ spinal forces in three tasks, and L₅S₁ loads in five and three tasks, respectively; however, offset and power curve normalization techniques were successful across all lumbar spine levels and all tasks. Offset normalization successfully removed the effect of body weight and maintained the influence of flexion angle on spinal forces. Thus, we recommend offset normalization to account for anthropometric differences in studies of spinal forces.

Bilateral Knee Joint Cooling on Anaerobic Capacity and Wheel Cadence during Sprint Cycling Intervals

We compared the effect of bilateral knee joint cooling with or without a pre-cooling warm-up on sprint cycling performance to a non-cooling control condition. Seventeen healthy young males (25 ± 2 years, 174 ± 6 cm, 70 ± 9 kg) performed three conditions in a counterbalanced order (condition 1: warming + cooling + cycling; condition 2: cooling + cycling; condition 3: cycling). For warming, a single set of cycling intervals (a 10 s sprint with maximal effort followed by a 180 s active recovery; resistive load 4% and 1% body mass for sprint and recovery, respectively) was performed. For cycling, five sets of cycling intervals were performed. For cooling, 20 min of bilateral focal knee joint cooling was applied. Peak and average values of anaerobic capacity and wheel cadence during each set across conditions were statistically compared. There was no condition effect over set (condition × set) in anaerobic capacity (F8,224 < 1.49, p > 0.16) and wheel cadence (F8,224 < 1.48, p > 0.17). Regardless of set (condition effect: F2,224 > 8.64, p < 0.0002), conditions 1 and 2 produced higher values of anaerobic capacity (p ≤ 0.05). Similarly (condition effect: F2,224 > 4.62, p < 0.02), condition 1 showed higher wheel cadence (p < 0.02) than condition 3. A bilateral joint cooling for 20 min with or without pre-cooling warm-up may improve overall sprint cycling capacity during five sets of cycling intervals when compared to the non-cooling condition.

Single and combined effect of kinesio tape and warm-up on sprint cycling performance

Background

The fact that kinesio tape may be capable to enhance muscle power would qualify it as practical tool to be considered during passive warm-up (WU) or coupled with active WU processes prior to power-based performance. Therefore, the aim of this study was to investigate the single and combined effect of kinesio tape (KT) and WU on sprint cycling performance.

Methods

In a repeated measure design, fifteen participants underwent six sessions to assess sprint cycling performance involving a combination of three taping conditions (without KT: NoKT; with KT positioned vertically over the thigh muscles KT; with KT positioned horizontally over the thigh muscles: Sham) with two pre-exercise routines (with WU: WU; without WU: NoWU) in a randomized order. Allometric scaling of peak power (PP) and average power (AP) values were considered for each sprint.

Results

KT-WU demonstrated the highest PP and AP with respect to the other conditions (p < 0.05), except for AP that was similar to Sham-WU (p > 0.05). Moreover, NoKT-NoWU showed the lowest PP and AP with respect to the other conditions (p < 0.05).

Conclusions

Overall, our findings suggest that kinesio tape might be a possible tool to be combined with an active WU routine, inducing benefit on sprint performance. Moreover, KT may be considered a potential strategy to include within a passive WU, perhaps where an active WU is not feasible. However, as the influence of KT on muscle function is still unclear, our results should not be overinterpreted.

Allometric scaling of power-force-velocity ergometry profiles in men

AIM

To examine the appropriate magnitude of allometric scaling of the force-velocity relationship according to body dimensions and to establish normative data for the power-force-velocity relationship for active men.

SUBJECTS AND METHODS

Ninety-seven participants completed a force-velocity test on a Monark cycle ergometer. Allometric exponents and percentile ranks were established for maximal power (Pmax), maximal force (F0) and maximal velocity (V0).

RESULTS

The mean (± SD) of Pmax, F0 and V0 were 1114.90 ± 160.60 W, 191.97 ± 26.51 N, and 227.87 ± 8.82 rpm, respectively. V0 was not related to any body size descriptors. Allometric exponents for Pmax, and F0 scaled for body mass were b = 0.77 (0.64-0.90) and 0.74 (0.61-0.86), respectively. Correlations between allometrically scaled Pmax and F0 with body mass were r = 0.002 (p = 0.984) and r = 0.008 (p = 0.940), respectively, suggesting that the allometric exponents derived were effective in partialling out the effect of body mass on Pmax and F0 results.

CONCLUSIONS

The allometric exponents and normative values of the current study provide a useful tool for comparing the scores of force-velocity tests between individuals without the confounding effect of body size.

Influence of increased body mass and body composition on cycling anaerobic power

Recent evidence suggests that not only body fat (BF) but high lean body mass (HLBM) adversely affects aerobic performance and may reduce aerobic endurance performance as well. However, the influence of body composition on anaerobic performance remains controversial. This study aimed to examine the effects of increased body mass (BM) and body composition on cycling anaerobic power. Peak power (PP) and mean power (MP) measurements were conducted in 2 groups of men with similar total BM but different body compositions resulting from (a) high level of BF [HBF group] or (b) high level of lean body mass [HLBM group] and in a control group. Peak power and MP were calculated in absolute values, relative to BM and lean body mass (LBM), and using allometric scaling. Absolute PP and MP were significantly higher in the HLBM group compared with the control and HBF groups. However, PP and MP relative to BM and using allometric scaling were similar in the HLBM and control groups, yet significantly higher than in the HBF group. There were no significant differences between groups in PP and MP when presented relative to LBM. Therefore, it seems that it is not BM but rather body composition that affects PP. Increased BM, resulting from increased LBM, does not adversely affect cycling anaerobic power, but a BM increase resulting from an increase in BF may adversely affect PP. Therefore, coaches and athletes should avoid excess BF to maximize cycling anaerobic power.