We investigated the effect of upper limb and shoulder girdle alignment on cervical muscle hardness and range of motion. [Participants and Methods] The participants were 20 healthy adult males. The measurement posture was the sitting position, and the upper limb and shoulder girdle alignment measurements were performed under three conditions: loading of both upper limbs, no loading of both upper limbs, no loading of the left upper limb. A biological tissue hardness tester and an ultrasonic three-dimensional motion analysis system were used to measure the cervical muscle hardness and range of motion, respectively. [Results] The cervical muscle hardness of the left and right trapezius muscles significantly reduced when both upper limbs were loaded, and that of the left trapezius muscle significantly reduced when there was no load on left upper limb. The cervical range of motion significantly increased in extension, rotation, lateral flexion when both upper limbs were loaded, and left rotation and right flexion significantly increased when there was no load on the left upper limb. [Conclusion] The results suggest that the upper limb and shoulder girdle alignment affects cervical muscle hardness and range of motion.
We investigated the effect on body sway of changes in craniocervical alignment with various sensory input restrictions. [Subjects] The subjects were 10 healthy adult males. [Method] The experimental task was to maintain standing for 20 s with the feet 10 cm apart. The sensory input restrictions were: no restrictions, sight restriction, somatic sensory restriction, and sight and somatic sensory restriction. For craniocervical alignment we used the neutral, extension, and flexion positions of the neck. We examined the effect of craniocervical alignment on body sway in each of the conditions. [Results] Under sight and somatic sensory restriction, body sway in neck extension was greater than in the other positions. [Conclusion] The results suggest that under conditions of compound sensory restriction, the importance of craniocervical alignment increases for postural maintenance.
This study investigated the factors of standing instability in elderly people after standing up quickly. [Participants and Methods] The participants were 15 healthy elderly men. Using a three-dimensional motion analysis system, we measured the movement of rising from a chair as quickly as possible and the standing posture after standing up. The effective value of the center of gravity in the anterior and posterior directions was used as the index of standing instability after standing up. We examined the correlation between the effective value and items of the kinematic data in the standing up motion. [Results] A negative correlation was shown between the effective value and the timing of the left hip extension moment, and a positive correlation was shown with the maximum value of the left knee joint moment. [Conclusion] The results suggest that a factor of standing instability after standing up quickly is eccentric control of the hip joint in bending of the trunk after seat off, and that standing instability may be affected by the strength of the knee extensor muscles related to hip joint control.
Purpose] The aim of this study was to clarify the relationships between postural stability in standing and head-neck position (H-N), and muscular strength of the toes (TMS) of elderly people. [Participants and Methods] The subjects were 30 healthy elderly men. Postural stability was assessed using the Index of Postural Stability (IPS). Subjects stood on a posturography force plate and IPS was measured with the H-N in the neutral, flexed, extended, side-flexed and rotated positions with the eyes open. TMS was measured using a toe-grip strength measuring instrument. [Results] IPS showed a significant difference between the H-N flexed and side-flexed positions. Significant positive correlations were found between IPS and TMS in 5 positions.[Conclusion] Postural stability was lower in the H-N side-flexed position than in the flexed position. Furthermore, when IPS was high, TMS also showed a tendency to be high.
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