Strength training and shoulder proprioception

Abstract

Context: Proprioception is essential to motor control and joint stability during daily and sport activities. Recent studies demonstrated that athletes have better joint position sense (JPS) when compared with controls matched for age, suggesting that physical training could have an effect on proprioception.

Objective: To evaluate the result of an 8-week strength-training program on shoulder JPS and to verify whether using training intensities that are the same or divergent for the shoulder's dynamic-stabilizer muscles promote different effects on JPS.

Design: Randomized controlled clinical trial.

Setting: We evaluated JPS in a research laboratory and conducted training in a gymnasium.

Patients or other participants: A total of 90 men, right handed and asymptomatic, with no history of any type of injury or shoulder instability.

Intervention(s): For 8 weeks, the participants performed the strength-training program 3 sessions per week. We used 4 exercises (bench press, lat pull down, shoulder press, and seated row), with 2 sets each.

Main outcome measure(s): We measured shoulder JPS acuity by calculating the absolute error.

Results: We found an interaction between group and time. To examine the interaction, we conducted two 1-way analyses of variance comparing groups at each time. The groups did not differ at pretraining; however, a difference among groups was noted posttraining.

Conclusions: Strength training using exercises at the same intensity produced an improvement in JPS compared with exercises of varying intensity, suggesting that the former resulted in improvements in the sensitivity of muscle spindles and, hence, better neuromuscular control in the shoulder.

Keywords: joint position sense; muscle spindles; neuromuscular control.

Figures

Figure 1.

Testing position.

Figure 2.

Absolute error values. Group 1: exercises performed with the same intensity; group 2: exercises performed with divergent intensities; control group: performed no upper body exercise. An interaction occurred between the factors of training group and time (P < .05).