Abstract
Walking involves small adjustments to maintain body balance. However, the demand for these adjustments may be different during downhill walking. The aim of this study was to analyze the effect of periodized downhill walking training on neuromuscular responses of knee flexors (KF). Seventeen active males (Age = 22.9 ± 3.9 years) were randomly assigned into two groups: control, level walking (CG, N = 8) and downhill walking (DWG, N = 9). Individuals performed the following procedures, in different days: 1) Maximal voluntary contractions to determine peak torque (PT) and rate of torque development (RTD) at different time intervals from the onset of muscle contraction. The test was performed before (Pre) and after (Post) a 4-week downhill walking training period. PT and peak RTD did not change after the training period (p > 0.05). However, there was significant increase in RTD at 150 ms and 200 ms after the onset of muscle contraction (p < 0.05). Additionally, the electromyographic activity (root mean square) of the biceps femoris and semitendineous muscles presented an increase after the training period (p < 0.05). Thus, downhill walking training can promote improvement RTD and muscle activity in the late phase of muscle contraction, which can have important implications during downhill walking, in which a rapid action of KF can help body balance against the disturbance generated by the slope.
Highlights
Gait implies a constant displacement of the center of mass (CM), which, of small magnitude, tends to provide a constant loss response and balance recovery
For a better understanding of gait, many authors have analyzed the behavior of certain muscle groups; the action of knee flexor muscles (KF) seems to be still poorly understood in the downhill walking condition (DW), and there are some contradictions in literature with respect to the action of these muscles in DW
Hunter et al.[7] verified that there is a significant increase in biceps femoralis muscle (BF) activity in the DW balance phase, which may help to explain the improvement in the rate of torque development (RTD) obtained in our study
Summary
Gait (ambulation or walking) implies a constant displacement of the center of mass (CM), which, of small magnitude, tends to provide a constant loss response and balance recovery This characteristic occurs even on a flat surface, which tends to offer the most natural condition for the performance of these adjustments[1,2]. On the other hand, during downhill walking, there is a tendency to increase the thrust ratio suffered due to the action of the force of gravity, producing accelerations that can generate disturbances in the posture and compromise the gait control[3,4] Such interferences may cause responses in specific areas responsible for gait stability and postural control on any surface, especially in the vestibular, visual and somatosensory systems, and generate adjustments in muscle control[5,6]. Reduction in the ability to produce rapid force, expressed through the impairment of RTD, of the plantar flexor and hip extensor muscles, has been related to greater risk of falls[9,10], especially in older adults, possibly due to the importance of this variable in the postural readjustment
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Brazilian Journal of Kinanthropometry and Human Performance
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
