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Jiroumaru T1, Fujitani R1, Bunki H1
1Shiga School of Medical Technology, Department of Physical Therapy, Shiga, Japan
Background: The importance of maintaining gait function has been emphasised in recent years because of its effect on extension of healthy ageing. The decreasing gait speed associated with ageing depends on a reduced stride length. Dysfunction of the hip joint muscles influences the gait ability, especially the iliopsoas as it relates to a prolonged stride length. Because the stride length is associated with falling and dementia in people of advanced age, analysis of the iliopsoas is important in terms of the timing of increased activity while walking and how to contribute to stride length. However, the role of the hip flexors, including the iliopsoas, in an increased stride length and pitch remains unclear.
Purpose: This study was performed to clarify the role of each hip flexor, including the iliopsoas, when these muscles show higher activity and how they contribute to an increased stride length and pitch.
Methods: Ten healthy men (age, 24.6 ± 2.8 years) were examined. During treadmill gait, the activity of the iliopsoas, sartorius, rectus femoris, and tensor fasciae latae was recorded using electromyography (EMG). For the gait task, the subjects walked on the treadmill with bare feet. They randomly performed three different tasks: normal gait (5 km/h), wider-length stride, and faster pitch. The speed of normal gait depended on each subject. However, they were required to follow the rhythm of a metronome in wider-length stride gait (80/min) and faster pitch gait (190/min). These gaits were measured with four cameras and three-dimensional motion analysis. The data were conversed to three-dimensional coordinate values using motion analysis software, and continuous three-gait cycles were analysed. A gait cycle was divided into four phases by hip joint motion: two stance phases and two swing phases.
Surface electrodes (0.5 × 0.5 cm) were placed at 1-cm intervals on the measured muscles along the muscle fibre. The EMG signal was recorded by a telemetry system with a 2000-Hz sampling frequency. After the signal was band-pass filtered (10-1000 Hz) and rectified with the root mean square, the EMG data were normalized based on the maximum voluntary contraction by manual muscle testing. The root mean square was compared with each muscle at each phase using one-way analysis of variance. If a significant difference was present between the walking tasks, Bonferroni analysis was performed. The level of significance was set at P 0.05.
Results: Higher activation of the iliopsoas was observed in the wider-stride gait during the later swing phase than in the faster pitch gait and normal gait (P 0.05). The rectus femoris activity was higher in the normal gait during the later stance phase than in the other gaits (P 0.05).
Conclusion(s): Therefore, the iliopsoas plays a role in extending the stride in the later swing phase, and the rectus femoris contributes to improving the speed in the later stance phase.
Implications: This study indicates that iliopsoas training may effectively increase the stride length, enabling people of advanced age to maintain and improve their stride length and helping to prevent falls and dementia in this population.
Keywords: Iliopsoas, stride length, electromyography
Funding acknowledgements: None.
Purpose: This study was performed to clarify the role of each hip flexor, including the iliopsoas, when these muscles show higher activity and how they contribute to an increased stride length and pitch.
Methods: Ten healthy men (age, 24.6 ± 2.8 years) were examined. During treadmill gait, the activity of the iliopsoas, sartorius, rectus femoris, and tensor fasciae latae was recorded using electromyography (EMG). For the gait task, the subjects walked on the treadmill with bare feet. They randomly performed three different tasks: normal gait (5 km/h), wider-length stride, and faster pitch. The speed of normal gait depended on each subject. However, they were required to follow the rhythm of a metronome in wider-length stride gait (80/min) and faster pitch gait (190/min). These gaits were measured with four cameras and three-dimensional motion analysis. The data were conversed to three-dimensional coordinate values using motion analysis software, and continuous three-gait cycles were analysed. A gait cycle was divided into four phases by hip joint motion: two stance phases and two swing phases.
Surface electrodes (0.5 × 0.5 cm) were placed at 1-cm intervals on the measured muscles along the muscle fibre. The EMG signal was recorded by a telemetry system with a 2000-Hz sampling frequency. After the signal was band-pass filtered (10-1000 Hz) and rectified with the root mean square, the EMG data were normalized based on the maximum voluntary contraction by manual muscle testing. The root mean square was compared with each muscle at each phase using one-way analysis of variance. If a significant difference was present between the walking tasks, Bonferroni analysis was performed. The level of significance was set at P 0.05.
Results: Higher activation of the iliopsoas was observed in the wider-stride gait during the later swing phase than in the faster pitch gait and normal gait (P 0.05). The rectus femoris activity was higher in the normal gait during the later stance phase than in the other gaits (P 0.05).
Conclusion(s): Therefore, the iliopsoas plays a role in extending the stride in the later swing phase, and the rectus femoris contributes to improving the speed in the later stance phase.
Implications: This study indicates that iliopsoas training may effectively increase the stride length, enabling people of advanced age to maintain and improve their stride length and helping to prevent falls and dementia in this population.
Keywords: Iliopsoas, stride length, electromyography
Funding acknowledgements: None.
Topic: Human movement analysis; Health promotion & wellbeing/healthy ageing
Ethics approval required: Yes
Institution: Aino University
Ethics committee: Ethics Review Board, Aino University
Ethics number: Aino-2013-02
All authors, affiliations and abstracts have been published as submitted.
