Association between abductor hallucis abductory force and navicular drop index, a predictive correlational study.

The role of intrinsic muscles of the foot in the medial longitudinal arch mechanism was investigated in several recent studies. It is determined that the abductor hallucis muscle (AHM) has an important role in dynamic support of the arch. Objective of our preliminary study was to establish a relationship between the navicular drop index (NDI) and the AHM abduction force. A single group exploratory design was used. The participants were 127 athletes aged 8-16 years (m/f 74/53; 11.99 ± 2.11 years; 156.21 cm ± 15.51 cm; 47.61 kg ± 13.96 kg; 2-5 training h/week), examined at a regular sport medical checkup. Abductor hallucis force was measured by a digital Algometer FPX 25/220, which is a newly developed approach that should be properly assessed in further studies to establish standardization and qualification of the algometer for this specific use. Navicular drop test has been performed as originally developed by Brody. Data were analyzed using Student's t-test, Mann-Whitney U test, contingency coefficients and logistic regression. Average NDI was found to be significantly different comparing the group with positive abduction force and the group that cannot perform the active abduction. Logistic regression indicated that the variable representing impossible active abduction was significantly associated with NDI. Preliminary results showed that there was a strong relationship between the hallux active abduction force and NDI in young athletes: the higher abduction force correlates to lower NDI. To determine clinical relevance of our investigation, further study is planned in which hallux active abduction force and NDI would be compared and correlated pre- and postspecific strengthening program.

Association Among Dyskinesia of the Lumbar Spine Segment, Inclination Angle of the Lumbosacral Spine, and Low Back Pain in Young Athletes: A Predictive Correlational Study.

OBJECTIVE: This predictive correlational study aimed to investigate the association among low back pain (LBP), dyskinesia of the lumbosacral spine segment (determined by inertial sensors), and inclination angles: the inclination angle of the lumbosacral spine (alpha), the inclination angle of the thoracolumbar spine (beta), and the inclination angle of the upper thoracic section (gamma). Our hypothesis was that young athletes with LBP had a particular dyskinesia: nonphysiological movements of the lumbosacral segment of the spine. METHODS: The study group consisted of 108 young athletes aged 10 to 16 years (male/female 44%/56%; 12.3 ± 1.8 years; 160.1 ± 12.0 cm; 51.1 ± 13.8 kg; 4.3 ± 2.4 training years; 3.7 ± 2.1 training h/wk). The alpha, beta, and gamma angles were measured with a digital inclinometer. The position of the lumbosacral segment at the maximum extension was determined with the inertial sensors, positioned at the 11th thoracic vertebra (T11), the third lumbar spine vertebra (L3), and the second sacral spine vertebra (S2). The data were analyzed using Student's t tests, tetrachoric correlation coefficients, and logistic regression. RESULTS: There was a significant statistical difference in alpha angles (t = 9.4, P < .001) and lumbar positions in extension (t = 6.4, P < .001) between groups with LBP and without LBP. The logistic regression indicated that LBP in young athletes was significantly associated with the increased alpha angle and nonphysiological lumbar position in extension measured by a sensor at the third lumbar spine vertebra. CONCLUSION: There was a strong association among LBP, increased inclination angle of the lumbosacral spine, and dyskinesia of the lumbar spine segment in young athletes.