Study Design: Counterbalanced experimental design study comparing a group of subjects with greater than or equal to 7° of forefoot varus (MFV) to a group with less than 7° of forefoot varus (LFV). Objectives: To investigate the effect of forefoot varus on single-limb stance postural stability (PS). Background: Impaired PS has been implicated as a potential risk factor for sustaining acute foot and ankle injuries. The identification of variables that deleteriously affect PS may be important in the prevention of future injuries. Methods and Measures: Postural stability of the MFV group (n = 20) and the LFV group (n = 12) was assessed during right and left single-limb stance and eyes-open and eyes-closed conditions. Standard deviations of the x-axis and y-axis ground reaction forces measured via a force platform were used to represent anteroposterior (AP) and mediolateral (ML) PS, respectively. The mean of 3 successful 5-second trials of each testing condition was calculated and used for subsequent data analysis using 3-way mixed-model ANOVAs with 1 between-subject and 2 within-subject factors. Results: The AP PS scores of the MFV group were significantly greater than those of the LFV group (P<.05). ML PS scores, although higher in the MFV group, were not significantly different from those of the LFV group. Both groups had significantly greater AP and ML PS scores during the eyes-closed versus the eyes-open condition (P<.05). Conclusions: The results suggest that the presence of greater than or equal to 7° of forefoot varus may significantly impair AP PS. The decreased stability associated with increased forefoot varus may be due to decreased joint congruity and consequently an increased reliance on soft tissue structures for stability.

J Orthop Sports Phys Ther. 2004;34(2):79-85. doi:10.2519/jospt.2004.1110

Key Words: balance, foot structure, ground reaction force, postural control

Study Design: A within-subjects repeated measures design. Objectives: To determine differences in the amount of vertical opening of the mandible among 3 different head positions. Background: Results from several studies have suggested that the position of the head and neck may affect temporomandibular joint function. Presently no standardized position of the head and neck has been recommended for measuring vertical opening of the mandible. Methods and Measures: Twenty males and 20 females (32.9 ± 8.3 years) participated in the study. We obtained 3 measurements of vertical mandibular opening using a millimeter ruler on each subject in the forward, neutral, and retracted head positions. Results: A 1 -way repeated measures analysis of variance followed by pairwise comparisons indicated that the vertical mandibular opening was significantly greater in the forward head position (44 ± 5.3 mm) than in the neutral head position (41.5 ± 4.8 mm) and in the retracted head position (36.2 ± 4.5 mm). In addition, vertical mandibular opening was significantly greater in the neutral head position than in the retracted head position. Interclass correlation coefficients for the 3 head positions ranged from 0.90 to 0.97 for intrarater, interrater, and day-to-day reliability. Conclusions: Head position is an important factor in determining the amount of vertical mandibular opening in healthy adults.

J Orthop Sports Phys Ther. 1999;29(2):127-130.

Key Words: temporomandibular, reliability, posture