Changes in Lower Limb Strength and Function Following Lumbar Spinal Mobilization.

OBJECTIVE: The purpose of this study was to investigate whether grade III passive lumbar rotational mobilization on L2-3 can improve hip flexor strength and performance in the single-leg triple-hop test in asymptomatic young adults. METHODS: Twenty-four participants (12 men, 12 women) aged from 19 to 26 years who were positive in the hip flexor "break" test were recruited in this study. They were randomly allocated to the treatment group or sham group. Isometric hip flexor torque (N·m) and single-leg triple-hop distance (cm) were measured before and after a passive lumbar rotational mobilization or a sham intervention. RESULTS: After the intervention, both the treatment and sham groups exhibited a significant increase in longest hop distance (P = .040 and .044, respectively). The treatment group had a significantly higher (3.41 ± 5.44%) positive percentage change in torque than the sham group (-2.36 ± 5.81%) (P = .02). CONCLUSION: The study results indicated a potential effect of grade III passive lumbar rotational mobilization in improving hip flexor strength. However, whether the improvement in hopping performance was the result of a treatment effect or a learning effect could not be determined.

Sonographic evaluation of the effect of long-term exercise on Achilles tendon stiffness using shear wave elastography.

OBJECTIVES: This study aimed to assess the feasibility of using quantitative shear wave elastography (SWE) to assess the stiffness (Young's modulus) of Achilles tendon and to investigate the effect of long-term weight-bearing exercise on the stiffness of human Achilles tendon by comparing the frequent and infrequent exercise groups. DESIGN: Case-control study. METHODS: A total of 36 healthy subjects aged 19-25 were recruited. Subjects were categorized into frequent and infrequent exercise groups dependent on their level of lower limb weight bearing exercise. B-mode and shear-wave ultrasound examination of Achilles tendon were performed. Measurements of the Achilles tendon stiffness were conducted with the foot position standardized by an ankle fixer. To evaluate inter and intra-operator reliability of Young's modulus measurements, each subject was scanned by three operators and each operator scanned the subject three times. RESULTS: The intra-operator reliability of Young's modulus measurements ranged between 0.803 and 0.845. The inter-operator measurement reliability was 0.585. Result showed that Achilles tendon on non-dominant ankle in frequent-exercisers (median: 320.1kPa) was significantly stiffer than that in infrequent-exercisers (median: 296kPa) (p<0.05), whereas there was no significant difference in Achilles tendon stiffness on dominant ankle between the two groups (p>0.05). CONCLUSIONS: Shear wave elastography is feasible for assessing the Achilles tendon's stiffness in vivo. The stiffness of Achilles tendon of frequent-exercisers was significantly higher than that of infrequent-exercisers on non-dominant ankle but not on dominant ankle. With the use of an ankle fixer, there was high repeatability and moderate reproducibility in SWE measurement of Achilles tendon stiffness.