Neuromuscular Electrical Stimulation and Isokinetic Training

Summary

The purpose of this study was to assess the effects of Neuromuscular Electrical Stimulation (NMES) associated to an isokinetic training program in both young healthy men and women. Twenty subjects (10 men, 10 women; 21±1.5 years) submitted both quadriceps femoris muscles to a strengthening program (3 sets of 10 isokinetic concentric repetitions at 30°/s) two days per week for 4 weeks. One limb was submitted only to the strength training (EX) while the other underwent the same training program but with NMES added to each contraction (Ex+NMES). The current used for NMES was Russian Current (frequency of 2500 Hz, 50 bursts/s and pulse duration of 200 µs). The evaluation protocol included isometric and isokinetic concentric extensor torques at 30°/s. Men increased their torque in both tested modalities in both limbs, with no difference between them. The angle of peak torque increased for the EX limb, showing an altered tension-length relationship, which did not occur for the Ex+NMES limb or for women. Women increased their torque for EX limb in both modalities, which only occured for isometric mode in the Ex+NMES limb. However, they showed a decrease in their acceleration time in Ex+NMES limbs, showing they could produce a muscular contraction more readily than they did before training. The results of this study found that the association between NMES and isokinetic concentric voluntary strength training does not improve strength gains of voluntary training itself for young healthy subjects of both genders. However, it could improve neuromuscular readiness to produce torque in women.

Conditions

• Healthy

Interventions

DEVICE

NMES

In the contralateral limb, the same protocol was repeated; however, each contraction was associated with overlapped NMES (Ex+NMES limbs).For the NMES, a symmetric double-phase sine-wave was used. Bearing wave frequency was of 2500 Hz, modulated in 50 bursts/s, with pulse duration of 200 µs, interburst interval of 10 ms. This configuration is known as "Russian current".

OTHER

Isokinetic exercise

Subjects realized training sessions twice a week with a 2-day minimum interval between the sessions, for 4 weeks. Each session included 5 min period of warm-up in a stationary bicycle, followed by 3 series of quadriceps stretching, as previously described. After being positioned at the isokinetic dynamometer, just as in the evaluation sessions, subjects firstly performed 3 sets of 10 maximum isokinetic concentric repetitions at the speed of 30º/s with one limb (EX limb), respecting the rest interval of 3 minutes between the sets.

Sponsors & Collaborators

• Universidade Federal de Sao Carlos

  lead OTHER

Principal Investigators

• Mariana A Avila, PT · Universidade Federal de Sao Carlos

• Tania F Salvini, PhD · Universidade Federal de Sao Carlos

• Jamilson S Brasileiro, PhD · Universidade Federal do Rio Grande do Norte

Study Design

Allocation

RANDOMIZED

Masking

SINGLE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

25 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2005-01-31

Primary Completion

2006-12-31

Completion

2007-07-31