Suzuki M1, Fujisawa H2, Suzuki H1, Murakami K1
1Tohoku Bunka Gakuen University, Sendai, Japan, 2Graduate School of Health and Environment Sciences, Tohoku Bunka Gakuen University, Sendai, Japan
Background: Movements requiring multi-joint motor coordination, such as the lateral step-up motion (LSU) and lateral step-down motion (LSD), are frequently required in daily life. Despite this, our literature review did not yield any reports that involved the analysis of LSU and LSD in comparison with side-steps (SS).
Purpose: The purpose of this study was to clarify the trajectory of center of gravity (COG), joint movement, and muscle activity during LSU and LSD in comparison with those during SS.
Methods: Twelve healthy males aged 21.6 ± 0.7 (mean±SD) years participated in this study. Informed consent was obtained from all participants. The SS length was calculated as 50% of the distance between the anterior superior iliac spine and the medial malleolus.
During LSU and LSD, the participants were instructed to step with the leg raised and down onto a 12-cm high stool. The participants were instructed to perform each task as fast as possible, and to maintain the final position for at least five seconds. The order of these tasks was SS, LSU, and LSD. The arithmetic mean was determined using data from three trials. Kinetic, kinematic, and electromyographic (EMG) recordings were performed. The ground reaction force was measured using two force plates (MG-1090, Anima, Japan) at a sampling frequency of 150 Hz. Kinematic measurements were performed using a Locus system (MA-5000, Anima, Japan) with six cameras operating at a sampling frequency of 150 Hz. EMG recordings were bilaterally performed on the gluteus maximus (GM), gluteus medius (Gm), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and soleus (SOL) using bipolar, disposable, surface electrodes at a sampling frequency of 1 kHz. The five phases of step motion durations were defined on the basis of ground reaction force and foot switch. PhaseⅠ is the first two-legged supporting period, in which the legs and feet are together. PhaseⅡ is the first single-sided supporting (the following leg) period. Phase Ⅲ is the wide-stance two-legged supporting period. Phase Ⅳ is the second single-sided supporting (the leading leg) period. PhaseⅤ is the second two-legged supporting period, with the legs and feet together.
Results: The activities of the GM and VL of the leading leg also indicated higher activities during LSU and LSD than during SS. The activities of the BF of the following leg also indicated higher activities during the LSU than during SS.
Conclusion(s): These results suggest that GM and VL activity of the leading leg controls the elevation of COG during LSU. Moreover, these results suggest that GM activity of the following leg controls the descent of COG during LSD.
Implications: These results suggest that LSU and LSD are clinically useful tests and muscle exercises in patients.
Keywords: Kinesiology, lateral step-up motion, lateral step-down motion
Funding acknowledgements: This study was unfunded.
Purpose: The purpose of this study was to clarify the trajectory of center of gravity (COG), joint movement, and muscle activity during LSU and LSD in comparison with those during SS.
Methods: Twelve healthy males aged 21.6 ± 0.7 (mean±SD) years participated in this study. Informed consent was obtained from all participants. The SS length was calculated as 50% of the distance between the anterior superior iliac spine and the medial malleolus.
During LSU and LSD, the participants were instructed to step with the leg raised and down onto a 12-cm high stool. The participants were instructed to perform each task as fast as possible, and to maintain the final position for at least five seconds. The order of these tasks was SS, LSU, and LSD. The arithmetic mean was determined using data from three trials. Kinetic, kinematic, and electromyographic (EMG) recordings were performed. The ground reaction force was measured using two force plates (MG-1090, Anima, Japan) at a sampling frequency of 150 Hz. Kinematic measurements were performed using a Locus system (MA-5000, Anima, Japan) with six cameras operating at a sampling frequency of 150 Hz. EMG recordings were bilaterally performed on the gluteus maximus (GM), gluteus medius (Gm), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and soleus (SOL) using bipolar, disposable, surface electrodes at a sampling frequency of 1 kHz. The five phases of step motion durations were defined on the basis of ground reaction force and foot switch. PhaseⅠ is the first two-legged supporting period, in which the legs and feet are together. PhaseⅡ is the first single-sided supporting (the following leg) period. Phase Ⅲ is the wide-stance two-legged supporting period. Phase Ⅳ is the second single-sided supporting (the leading leg) period. PhaseⅤ is the second two-legged supporting period, with the legs and feet together.
Results: The activities of the GM and VL of the leading leg also indicated higher activities during LSU and LSD than during SS. The activities of the BF of the following leg also indicated higher activities during the LSU than during SS.
Conclusion(s): These results suggest that GM and VL activity of the leading leg controls the elevation of COG during LSU. Moreover, these results suggest that GM activity of the following leg controls the descent of COG during LSD.
Implications: These results suggest that LSU and LSD are clinically useful tests and muscle exercises in patients.
Keywords: Kinesiology, lateral step-up motion, lateral step-down motion
Funding acknowledgements: This study was unfunded.
Topic: Human movement analysis
Ethics approval required: Yes
Institution: Tohoku Bunka Gakuen University
Ethics committee: The Research Ethics Committee
Ethics number: n.14-14
All authors, affiliations and abstracts have been published as submitted.
