Profiling the Isokinetic Muscle Strength of Athletes Involved in Sports Characterized by Constantly Varied Functional Movements Performed at High Intensity: A Cross-Sectional Study

Abstract

Background: Constantly varied functional movements performed at high intensity (FMHI) is a type of strength and general conditioning program that has gained widespread popularity in recent years. The very intense exercises performed with lower and upper limbs may create muscular asymmetry or imbalance between agonist and antagonist muscles, and therefore the characterization of isokinetic muscle strength, side-to-side difference, and balance ratios for lower and upper limbs may contribute to a better understanding of the modality characteristics.

Objective: To evaluate the knee and shoulder strength of FMHI athletes of both sexes.

Design: Cross-sectional study.

Setting: Exercise physiology laboratory.

Participants: Sixty FMHI athletes (30 M/30 W) with more than 2 years' experience.

Methods: Athletes performed isokinetic tests in both lower and upper limbs: concentrically at 60°/s and 240°/s and eccentrically at 240°/s.

Main outcome measurements: Isokinetic peak torque of knee flexor and extensor and shoulder internal and external rotator muscles. Conventional and functional strength balance ratios and side-to-side strength difference.

Results: Concentric peak torque values relative to total body mass for shoulder and knee joints were higher in men than women on both sides. Eccentric peak torque values for knee flexor-dominant and extensor-nondominant limbs showed no difference between the sexes. The knee conventional strength balance ratio for dominant and nondominant sides in women (51.5% ± 7.0% and 51.0% ± 7.1%, respectively) and for dominant and nondominant sides in men (54.4% ± 15.2% and 51.5% ± 9.9%, respectively) were no different between the sexes or limbs. The shoulder conventional strength balance ratio was higher in women (78.1 ± 13.2%) than in men (67.6% ± 10.9%) on the nondominant side. Knee and shoulder functional strength balance ratios in nondominant limbs were higher for women than men. Both sexes presented no side-to-side difference for knee joints or muscles, or for shoulder IR muscles, but ER was stronger in dominant limbs.

Conclusions: These data from highly trained FMHI athletes can be compared to that of other athletes to help determine individual weaknesses, strengths, and imbalances, and may be useful for designing training programs.

Level of evidence: III.