Trunk and Upper Body Fatigue Adversely Affect Running Economy: A Three-Armed Randomized Controlled Crossover Pilot Trial

The Relationship between Ergometric Treadmill or Bicycle Performance and Isokinetic Trunk Strength - a Retrospective Analysis

The relationship between trunk strength and athletic performance is well known. In the past, trunk strength and athletic performance were measured in field tests. Previous studies encouraged sport-specific analyses. The goal of this study was to investigate whether there is a relation between ergometrically measured treadmill or bicycle endurance and isokinetic trunk strength. This retrospective analysis included 1334 bicycle and 1838 treadmill ergometry examinations in 1149 subjects. Bicycle and treadmill ergometer performance were analysed in relation to isokinetic trunk strength. Statistics were performed by Pearson correlation and mixed or generalised linear models. Higher treadmill and bicycle power correlated with higher isokinetic trunk strength, with highest absolute trunk strength in the treadmill group. For both running and cycling endurance, a positive correlation with trunk strength could be quantified in regression models. Increased ergometry endurance and lower flexion/extension ratios are connected weakly. Ergometry performance had the strongest correlation with extension trunk strength (r=0.312-0.398 for bicycle ergometry and r=0.168-0.229 for treadmill ergometry, p<0.001). We encourage prospective studies using both kinds of ergometry to evaluate the effect of trunk strengthening to enhance sport-specific endurance performance. Weight-adapted trunk strength values showed overall greater correlation to trunk strength and we recommend the use of weight-adapted values.

Changes in acceleration load as measured by inertial measurement units manifest in the upper body after an extended running task

The purpose of this study was to investigate the behaviour of physiological load measures as well as ground reaction forces (GRF) and acceleration load during a prolonged running task that simulated the running demands of an intermittent team sport. Nineteen males completed a maximal aerobic fitness test and an extended running protocol across two sessions. Participants wore a portable metabolic system, and four inertial measurement units (IMU), one on each foot, the lower back and upper back. GRF were measured via an instrumented treadmill. Change in metabolic, IMU and GRF variables across five blocks during the running protocol were assessed using a one-way repeated measures ANOVA. The running protocol elicited large increases in heart rate and oxygen consumption over time. No statistically significant changes in any peak impact accelerations were observed. Resultant acceleration area under the curve (AUC) increased at the lower and upper back locations but was unchanged at the foot. GRF active peak but not impact peak increased during the prolonged run. The results of this study indicate that the effect of an extended running task on IMU measures of external mechanical load is manifested in the upper body, and is effectively measured by AUC.