NORMATIVE VALUES FOR ISOMETRIC MUSCLE STRENGTH OF HIP FLEXORS WITH HAND-HELD DYNAMOMETER IN UNIVERSITY ATHLETES

Abstract

Background

Establishing normative strength data can assist professionals in guiding post-injury rehabilitation and be a criterion for deciding discharge for sports return.

Objectives

To establish reference values for isometric hip flexor muscle strength in college athletes.

Methods

This was a cross-sectional observational study. The athletes were submitted to an isometric muscle strength evaluation of the hip flexors through a hand-held dynamometer (Medeor Medtech Tecnologia em Saúde Industria e Comercio Ltda). The athletes remained in dorsal decubitus position on a stretcher, with the tested leg flexed 10 cm above the surface to start the test. The dynamometer was positioned on the anterior part of the leg, above the talotibial joint line. The lever arm was defined as the distance, in meters (m), between the anterior superior iliac spine and the dynamometer application point. The athletes performed three isometric contractions of 5 seconds, with a rest interval of 30 seconds between repetitions. If there was a discrepancy greater than 10% in the first three repetitions, a fourth repetition was performed. The isometric force data were expressed in kilogram-force (Kg/f) and converted to newton (N) for the calculation of torque (N.m). The normality of the data was verified using the Shapiro-Wilk test. The mean and standard deviation were calculated, followed by and by independent samples t-test. A significance level of (p > 0.05) was adopted.

Results

Thirteen female athletes (22 ± 2.19 years; 1.63 ± 0.06 m and 63.5 ± 16.9 kg) and 14 male athletes (23.85 ± 6.97 years; 1.75 ± 0.06 m and 72.8 ± 8.6 kg) participated in the study, totaling 27 college athletes. The athletes were classified according to the International Physical Activity Questionnaire (IPAQ) as Very Active (29.62%), Active (55.55%) and Irregularly Active (14.81%). Male athletes produced significantly more torque (109.36 ± 43.70 N.m; CI 84.12 - 134.59 N.m) when compared to female athletes (73.05 ± 14.26 N.m; CI 64.43 - 81.67 N.m).

Conclusion

This study provides a normative database on isometric hip flexor strength measured with a hand-held dynamometer. In general, differences in strength were present between the sexes, with men showing higher torque values compared to women.

Implications

The isokinetic dynamometer is the gold standard instrument for quantifying muscle strength. However, it is not accessible to all athletes. Therefore, we sought an alternative for the quantification of muscle strength in an affordable way. These data provide a description of hip flexor muscle strength in college athletes in order to assist professionals in post-injury rehabilitation, and to be a discharge criterion for sports return.