Évaluation isocinétique chez le lombalgique. Rôle respectif de la familiarisation et de la rééducation dans l'évolution des performances

Characteristics of Back Muscle Strength in Patients with Scheduled for Lumbar Fusion Surgery due to Symptomatic Lumbar Degenerative Diseases

Study Design

Cross sectional study.

Purpose

To evaluate characteristics of back muscle strength in patients scheduled for lumbar fusion surgery.

Overview of Literature

Little is known regarding muscle strength in patients with symptomatic lumbar degenerative diseases who require fusion surgery.

Methods

Consecutive 354 patients scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases were approached for participation. 316 patients were enrolled. Before surgery, muscle strength was assessed by measuring maximal isometric extension strength at seven angular positions (0°, 12°, 24°, 36°, 48°, 60°, and 72°) and mean isometric strength was calculated. The Oswestry Disability Index (0-100) and visual analogue scale (0-100) for back pain were recorded. Muscle strength was compared according to gender, age (<60, 60-70, and ≥70 years) and scheduled fusion level (short, <3; long, ≥3).

Results

Isometric strength was significantly decreased compared with previously reported results of healthy individuals, particularly at extension positions (0°-48°, p<0.05). Mean isometric strength was significantly lower in females (p<0.001) and older patients (p<0.05). Differences of isometric strength between short and long level fusion were not significantly different (p>0.05). Isometric strengths showed significant, but weak, inverse correlations with age and Oswestry Disability Index (r<0.4, p<0.05).

Conclusions

In patients with symptomatic lumbar degenerative diseases, back muscle strength significantly decreased, particularly at lumbar extension positions, and in females and older patients.

Postactivation potentiation biases maximal isometric strength assessment

Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s⁻¹versus 727 ± 158 N·m·s⁻¹), and RMS (59.1 ± 12.2% RMS_MAX   versus 54.8 ± 9.4% RMS_MAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

Comparison of isokinetic exercise versus standard exercise training in patients with chronic low back pain: a randomized controlled study

OBJECTIVE

To compare the effectiveness of an isokinetic exercise programme and a standard exercise programme in patients with chronic low back pain in terms of pain, mobility, disability, psychological status and muscle strength.

DESIGN

A randomized controlled trial.

SETTING

An outpatient rehabilitation clinic.

SUBJECTS

A total of 40 patients with low back pain were included in the study.

INTERVENTIONS

Patients with low back pain were randomly allocated into group 1 (n=20, isokinetic exercises) and group 2 (n=20, standard exercise).

MAIN MEASURES

Outcome measures included a visual analogue scale (VAS) for pain, fingertip-to-floor test for spinal mobility, Modified Oswestry Low Back Disability Questionnaire (MOLBDQ), Beck Depression Inventory and isokinetic muscle testing.

RESULTS

The isokinetic and standard exercise groups demonstrated significant improvement in the VAS, fingertip-to-floor test, MOLBDQ, Beck Depression Inventory scores, and muscle strength compared with the baseline that persisted until the end of the first month (P<0.05). Comparison of both exercise groups in terms of these parameters obtained at the end of the treatment and at the first month after treatment showed no significant difference (P>0.05).

CONCLUSION

Isokinetic and standard exercise programmes have an equal effect in the treatment of low back pain, with no statistically significant difference found between the two programmes. The standard exercise programme was easily performed and had a low cost, making it the preferred option for exercise.

[Does exercise therapy for chronic lower-back pain require daily isokinetic reinforcement of the trunk muscles?]

OBJECTIVE

The goal of this study was to determine the benefits of a functional retraining programme (with or without daily isokinetic reinforcement of the trunk muscles) in patients with lower-back pain.

METHOD

Two groups of 30 patients took part in the study. The control group (CG) underwent a four-week reconditioning program in a day hospital, whereas a second interventional group (IG) additionally performed daily isokinetic training of the trunk muscles. Three evaluations were carried out: before hospitalization (T1), immediately after hospitalization (T2) and three months postrehabilitation (T3).

RESULTS

We observed an improvement in each parameter after rehabilitation, regardless of the group. A decrease in the DALLAS scores revealed a reduced impact of lower-back pain on the patients' lives. Pain experienced fell by 24%, analgesic treatment was significantly decreased (CG: -53%; IG: -56%), muscle endurance was improved (quadriceps: +30%, abdominal muscles: +20%, paraspinal muscles: +23%, quadratus lumborum: +33%) and the patients were more supple, as revealed by a decrease in the finger-to-ground distance (at T1, CG: 12.9+/-6.1cm; IG: 13.6+/-5.5 cm at T1; CG: 2.2+/-5.4 cm; IG: 2.8+/-5.1cm at T2). The sole difference for CG and IG at T2 resulted from an improvement in the performance of the trunk extensor muscles, which was significantly greater in the IG (CG: +14%; IG: +20%). Three months after rehabilitation, the benefits were still present for the two groups and, indeed, were even greater for certain parameters.

CONCLUSION

Regardless of the protocol, the patients improved in both physical and psychological terms and these improvements were maintained over a short period, at least. Our results confirmed that one functional recovery programme is not superior to another for patients with lower-back pain.