Effect of gender on the quadriceps-to-hamstrings coactivation ratio during different exercises.

CONTEXT: Coactivation ratio of quadriceps to hamstring muscles (Q:H) and medial to lateral knee muscles (M:L) contributes to the dynamic stability of the knee joint during movement patterns recommended during rehabilitation and important for daily function. OBJECTIVE: To compare the quadriceps-to-hamstring and medial-to-lateral knee muscles' coactivation ratios between men and women during the following closed kinetic chain exercises performed on a balance board: forward lunge, side lunge, single-leg stance, and single-leg squat. DESIGN: Cross-sectional. PARTICIPANTS: 20 healthy subjects (10 female and 10 male). MAIN OUTCOME MEASURES: Surface electromyography was used to measure the activation level of quadriceps (vastus lateralis and medialis) and hamstrings (biceps femoris and medial hamstrings) during forward- and side-lunge, single-leg-stance, and single-leg-squat exercises. Subjects were instructed during each exercise to move into the test position and to hold that position for 15 s. EMG was recorded during the 15-s isometric period where subjects tried to maintain a "set" position while the foot was on a balance board. Analysis of variance was used for statistical analysis. RESULTS: There was a significant exercise-by-gender interaction for Q:H ratio (F3,48 = 6.63, P = .001), but the exercise-by-gender interaction for M:L ratio was not significant (F3,48 = 1.67, P = .18). Women showed larger Q:H ratio in side-lunge exercises than men (P = .002). Both genders showed larger M:L and lower Q:H ratio in a single-leg-stance exercise than in the other exercises. CONCLUSIONS: The results indicate that the forward- and side-lunge and single-leg-squat exercises should not be recommended as exercise where a balanced coactivation between quadriceps and hamstring muscles is warranted. Single-leg-stance exercise could be used when seeking an exercise where the ratio is balanced for both women and men.

Activation of selected ankle muscles during exercises performed on rigid and compliant balance platforms.

STUDY DESIGN: Experimental laboratory study. OBJECTIVE: To compare how the design of 2 balance platforms affects ankle musculature activation for various weight-bearing exercises. BACKGROUND: Balance platforms are widely used in both training and rehabilitation, and a better understanding of how platform design and type of exercise modify the demands on the ankle musculature may be helpful in staging exercise progression. METHODS: Surface electromyography was used to measure the activation level of the fibularis longus, tibialis anterior, and medial gastrocnemius while performing 4 exercises on 2 different balance platforms (compliant and rigid). Twenty-four (12 females, 12 males) healthy, sedentary subjects participated in the study. Analysis of variance was used for statistical analysis. RESULTS: There was no significant interaction between balance platforms and exercises (P>.05), and the type of platform did not influence muscle activation for the 3 muscles monitored (P>.05). The highest activation level for the fibularis longus and medial gastrocnemius was obtained during single-leg stance, and for the tibialis anterior during the single-leg squat (P<.05). CONCLUSION: In this study, although the demands on the ankle musculature were similar for selected exercises performed on a compliant versus a rigid balance platform, muscle activation level varied based on the exercise.

Effects of lateralisation and gender on temporal lobe ictal behaviour associated with hippocampal sclerosis.

INTRODUCTION: Information derived from animal models and neuroradiological studies in humans indicates that males and females exhibit differences in the functional and anatomical organisation of the brain. This study aimed to evaluate the effect of gender in ictal behaviour considering lateralisation in a group with homogeneous pathology. METHODS: Patients with hippocampal seizures who underwent temporal lobectomy and who were seizure-free during one year of follow-up were selected. Surgery was performed on the right side in 27 patients and on the left side in 21. Videotape recordings of the patients were reviewed in order to investigate ictal behaviour. There were 42 seizure episodes in 20 males and 40 in 21 females. For auras, 48 patients' data were reviewed. Ictal behaviour was evaluated taking into consideration the lateralisation of seizures and gender differences. RESULTS: Ictal vocalisation was significantly higher in females with right temporal lobe epilepsy (RTLE) (P < 0.05). Forced head deviation was significantly higher in males with left temporal lobe epilepsy (LTLE) (P < 0.03) and in females with RTLE (P < 0.0001). Unforced head deviation was significantly higher in males with RTLE (P < 0.002). Ipsilateral eye deviation was significantly higher in RTLE, with no differences between males and females. Postictal coughing was significantly higher in RTLE, again with no differences between males and females (P < 0.03). With regard to automatisms, posturing and nose wiping, there was no difference between right and left temporal lobe seizures or between genders. CONCLUSIONS: To the best of our knowledge, this study is the first demonstrating differences in ictal behaviour between females and males, thus showing that gender is related to different functional and anatomical organisations of the human brain.