Comparison of muscle activity of the lower limbs while running on different treadmill models.

Treadmill running is a common method of exercise and to study human locomotion. Research has examined the kinematics and kinetics of overground and treadmill running, but there has been less focus on the levels of muscle activity during treadmill running. We investigated if muscle activity is different while running overground compared to running on a variety of treadmills. A total of 11 healthy individuals ran at 3 speeds (2.6, 3.6, 4.5 m/s) under 4 different running conditions (3 treadmills, overground). The three treadmills included a typical home exercise treadmill, a midsize commercial research treadmill, and a large, instrumented research treadmill. Surface EMG of the tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF) and biceps femoris (BF) muscles were measured for each running condition. The integrated EMG was computed for each running condition for the stance and swing phase, as well as 100 ms before and after the heel-strike. Friedman analysis revealed significant effects during the stance phase for GM and RF at all speeds, such that muscle activation was lower on the treadmills relative to overground. During the stance phase at faster speeds, the muscle activity was higher for the TA and lower for the BF while running on the different treadmills compared to overground running. Before heel-strike, the TA was significantly less active during treadmill compared to overground running at 2.6 m/s and the RF showed significantly higher activity at 3.6 m/s and 4.5 m/s while running on the different treadmills. Summarizing, differences were mainly observed between the different treadmill conditions relative to overground running. Muscle activation differences between the different treadmill conditions were observed at faster running speeds for RF during the pre-heel-strike phase only. Different types of treadmills with different mechanical properties affects the muscle activity during stance phase as well as in preparation to heel-strike. Additionally, the muscle activity is greater during overground compared to treadmill running during the stance phase for the GM, BF, and RF.

[Predictors of the Use of Different Occupational Rehabilitation Measures: A Comparison of Integration Measures, Partial Qualifications and Full Training]. / Prädiktoren für die Inanspruchnahme unterschiedlicher Leistungen zur Teilhabe am Arbeitsleben: Ein Vergleich von Integrationsmaßnahmen, Teilqualifizierungen und Vollausbildungen.

PURPOSE: Occupational rehabilitation is an essential part of supporting return to work by the statutory pension insurance institutes. It is useful if health-related restrictions threaten the ability to work. There are various forms of occupational rehabilitation which differ considerably in terms of content, structure, duration, intensity of care and costs. The aim of the study was to identify personal characteristics that can influence the use of three different occupational rehabilitation measures. METHODS: All rehabilitants who underwent an occupational rehabilitation in the cooperating occupational rehabilitation centre (Berufsförderungswerk) from 2009 to 2014 under the funding of the German Federal Pension Fund were included in the analysis. A multinomial logistic regression was calculated in order to obtain information on the predictors of utilization of three occupational rehabilitation measures (integration measure, partial qualification, full training). As potential influencing factors, various sociodemographic characteristics as well as various parameters that reflect the employment status of rehabilitants in the previous year were included in the model. RESULTS: The analyses included a total of 934 rehabilitants who had completed an integration measure (n=443), partial qualification (n=315) or full training (n=176). In the final logistic regression model, gender (p<0.0001), age (p<0.0001), education level (p=0.0033), driving license (p<0.0001), willingness to move (p=0.0012), recognized disability (p=0.0404) and the employment status in the third month before the start of the measure (p=0.0020) proved to be significant predictors of utilization. CONCLUSION: The utilization of the different occupational rehabilitation measures is determined by various influencing factors. In particular, the more extensive and cost-intensive full training are more likely to be taken up by younger, male and more highly qualified rehabilitants.

Application of functional data analysis to explore movements: walking, running and jumping - A systematic review.

Background Signals are continuously captured during the recording of motion data. Statistical analysis, however, usually uses only a few aspects of the recorded data. Functional data analysis offers the possibility to analyze the entire signal over time. Research question The review is based on the question of how functional data analysis is used in the study of lower limb movements. Methods The literature search was based on the databases EMBASE, PUBMED and OVID MEDLINE. All articles on the application of functional data analysis to motion-associated variables trajectories, ground reaction force,electromyography were included. The references were assessed independently by two reviewers. Results In total 1448 articles were found in the search. Finally, 13 articles were included in the review. All were of moderate methodological quality. The publication year of the studies ranges from 2009 to 2019. Healthy volunteers and persons with cruciate ligament injuries, knee osteoarthritis, gluteal tendinopathy, idiopathic torsional deformities, slipped capital femoral epiphysis and chronic ankle instability were examined in the studies. Movements were analyzed on basis of kinematics (3D motion analysis), ground reaction forces and electromyography. Functional Data Analysis was used in terms of landmark registration, functional principal component analysis, functional t-test and functional ANOVA. Significance Functional data analysis provides the possibility to gain detailed and in-depth insights into the analysis of motion patterns. As a result of the increase in references over the past year, the FDA is becoming more important in the analysis of continuous signals and the explorative analysis of movement data.

Force measurements during running on different instrumented treadmills.

One method to determine the forces produced during running is to conduct extensive kinematic and kinetic analysis. These analyses can be performed by having an individual perform repeated over-ground running trials or simply run continuously on an instrumented treadmill. The forces produced during over-ground running may not be the same as the forces during treadmill running and these differences could be attributed to a number of factors, including the design of the instrumented treadmill. The purpose of this paper was to determine whether there are differences in force measurements on different instrumented treadmill setups in comparison to over-ground running and to correct for any of these differences using a theoretical model. 11 participants ran on three different treadmills and performed over-ground running at 2.7, 3.6, and 4.5 m/s. Ground reaction forces were measured via force plates and an instrumented pressure insole. We found that the magnitude of the vertical ground reaction force differed between the three treadmills and over-ground running. The difference in ground reaction forces estimated by the pressure insole and the treadmill-force-plate system or instrumented treadmill can be explained by a three degree of freedom mechanical model of a person running on a treadmill and this model could potentially be used to correct for errors in force measurement from instrumented treadmills. The model included a force plate, a treadmill, and a wobbling mass with varying natural frequencies and damping characteristics, and constant masses. These findings provide researchers a method to correct forces from an instrumented treadmill set-up to determine a close approximation of the actual forces experienced by a participant during treadmill running.