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Electromyographic developmental changes in one individual from newborn stepping to mature walking
Tsutomu Okamoto1, Kayoko Okamoto, Paul D Andrew
1Department of Liberal Arts, Kansai Medical University, Uyama-Higashi-Machi 18-89, Hirakata-shi, Osaka 573-1136, Japan.
Insights
Human bipedal locomotion development involves significant electromyographic (EMG) changes in lower limb muscles. Muscle activity shifts from co-contraction to reciprocal patterns, reflecting improved strength and neuromaturation for better balance control.
Area of Science:
- Neuroscience
- Biomechanics
- Developmental Biology
Background:
- Human bipedal locomotion is a complex motor skill that develops throughout early childhood.
- Understanding the neuromuscular control of gait development is crucial for identifying potential developmental abnormalities.
Purpose of the Study:
- To investigate electromyographic (EMG) changes in lower limb muscles during the development of human bipedal locomotion from infancy to early childhood.
- To correlate observed EMG patterns with developmental milestones in posture and balance control.
Main Methods:
- Electromyographic (EMG) recordings of tibialis anterior, lateral gastrocnemius, vastus medialis, rectus femoris, biceps femoris, and gluteus maximus muscles were obtained from a single subject.
- Data were collected from 3 weeks of age until 7 years, encompassing three stages of gait: primitive, supported, and independent walking.
Main Results:
- Muscle activity patterns evolved from excessive co-contraction of antagonist muscles to more reciprocal activation patterns across developmental stages.
- During the stance phase, a shift occurred from continuous activity of posterior muscles (lateral gastrocnemius, biceps femoris) to focused bursts.
- These changes were observed over the first two years of independent walking.
Conclusions:
- The developmental trajectory of lower limb muscle activity during walking is influenced by increasing postural strength and neuromaturation.
- Improved balance control, a result of neuromaturation, plays a significant role in refining gait mechanics.
- This study provides insights into the neuromuscular adaptations underlying the acquisition of mature bipedal locomotion.
Abstract:
Electromyographic (EMG) recordings of the lower limbs were made from a girl from 3 weeks after birth until 7 years of age to determine EMG changes in the development of human bipedal locomotion. Recordings were taken from the tibialis anterior (TA), lateral gastrocnemius (LG), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), and gluteus maximus muscles. In each of three developmental stages of gait, primitive walking, supported walking, and independent walking, muscle activity progressed from excessive co-contraction of mutual antagonists to reciprocal patterns. For the stance limb, the predominant reciprocal pattern to emerge was continuous activity of the posteriorly located LG and BF as opposed to the anteriorly located TA and RF. In independent walking this preponderance of maintained activity by the LG and BF in stance phase gradually waned over the first 2 years of walking to focused bursts of activity. The developmental changes observed in this girl appear to have been attributable to changes in posture reflecting increased strength and to improvements in control of balance reflecting neuromaturation.