Twenty adolescent patients (18 girls and 2 boys) with scoliosis ranging from 15 degrees-41 degrees in their major curve were treated with a progressive resistive training program for torso rotation. All patients demonstrated an asymmetry of rotation strength measured on specialized equipment, and surface electrode electromyograms showed inhibition of lumbar paraspinal muscles. Sixteen of 20 patients demonstrated curve reduction, and no patient showed an increase in curve.

The authors studied 12 adolescent patients with scoliosis (10 girls and 2 boys) who were 11 to 16 years old and had curvatures ranging from 20 degrees to 60 degrees. Seven were right thoracic curves and five were thoracolumbar with double curves. When tested on the MedX Torso Rotation Machine, both sides were unequal in their torso rotation strength all patients. Myoelectric activity was asymmetric in both sides and in abdominal and paraspinal muscles of all patients. These asymmetries were corrected completely with torso rotation, which was associated with significant strength gains. Strength gains ranged from 12% to 40%. A 16-year-old girl with a 60 degree lumbar curve progressed and had surgery. None of the remaining patients progressed, and 4 of the 12 had decreases in their curvatures from 20 degrees to 28 degrees. None of the patients used braces during this study.

STUDY DESIGN: Prospective clinical trial.


OBJECTIVES: To test the hypothesis that quantified trunk rotational strength training will equalize any strength asymmetry, increase strength overall, and stabilize adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Bracing, the only generally accepted form of adolescent idiopathic scoliosis nonoperative therapy, has many shortcomings. Paraspinal muscle abnormalities, which have been extensively documented in these patients, are generally considered to be secondary. A normal female's trunk strength in flexion and extension decreases from her juvenile to adolescent years, whereas a male's increases.


METHODS: Patients received a 4-month supervised followed by a 4-month home trunk rotational strength training program. Trunk rotational strength was measured in both directions at 5 positions at baseline, 4 months, and 8 months. The patients were followed clinically.


RESULTS: Fifteen patients (12 females and 3 males), with an average age of 13.9 years and an average main Cobb of 33 degrees were enrolled. At baseline there was no significant asymmetry. After 4 months of supervised strength training, involving an average of 32 training sessions, each lasting about 25 minutes, their strength had significantly increased by 28% to 50% (P\<0.005 to P\<0.001). After 4 months of unsupervised home strength training their strengths were unchanged. The 3 patients with baseline curves of 50 to 60 degrees all had main or compensatory curve progression and 2 had surgery. For patients with 20 to 40-degree curves, survivorship from main curve progression of greater or equal to 6 degrees was 100% at 8 months, but decreased to 64% at 24 months.


CONCLUSIONS: Quantified trunk rotational strength training significantly increased strength. It was not effective for curves measuring 50 to 60 degrees. It appeared to help stabilize curves in the 20 to 40-degree ranges for 8 months, but not for 24 months. Periodic additional supervised strength training may help the technique to remain effective, although additional experimentation will be necessary to determine this.

BACKGROUND: Recent reports have suggested a rotational strength weakness in rotations to the concave side in patients with idiopathic scoliosis. There have been no studies presenting normative values of female adolescent trunk rotational strength to which a comparison of female adolescents with idiopathic scoliosis could be made. The purpose of this study was to determine trunk rotational strength asymmetry in a group of female adolescents with AIS and a comparison group of healthy female adolescents without scoliosis.


METHODS: Twenty-six healthy adolescent females served as the healthy group (HG) (average age 14 years) and fourteen otherwise healthy adolescent females with idiopathic scoliosis served as the idiopathic scoliosis group (ISG) (average age 13.5 years, average Cobb 28 degrees ). Participant's isometric trunk rotational strength was measured in five randomly ordered trunk positions: neutral, 18 degrees and 36 degrees of right and left pre-rotation. Rotational strength asymmetry was compared within each group and between the two groups using several different measures.


RESULTS: The HG showed strength asymmetry in the 36 degrees pre-rotated trunk positions when rotating towards the midline (p < 0.05). The ISG showed strength asymmetry when rotating towards the concavity of their primary curve from the neutral position (p < 0.05) and when rotating towards the concavity from the 18 degrees (p < 0.05) and 36 degrees (p < 0.05) concave pre-rotated positions. The ISG is significantly weaker than the HG when rotating away from the midline toward the concave (ISG)-left (HG) side from the concave/left pre-rotated 18 degrees (p < 0.05) and 36 degrees (p < 0.05) positions.


CONCLUSION: The AIS females were found to be significantly weaker when contracting toward their main curve concavity in the neutral and concave pre-rotated positions compared to contractions toward the convexity. These weaknesses were also demonstrated when compared to the group of healthy female adolescent controls. Possible mechanisms for the strength asymmetry in ISG are discussed.

Quantified trunk rotational strength training has shown promise as a non-operative management option for individuals with AIS. The purposes of our study are to test whether a quantified trunk rotational strength training protocol can increase trunk strength and stabilize or decrease curve size. Seven adolescents with AIS (5 female 2 male; mean 14 yrs +/- 2.6 yrs; mean Cobb 28 degrees +/- 6 degrees range 20 degrees -37 degrees) underwent four months of supervised trunk rotational strength training, and repeat strength test. Trunk strength in both directions increased significantly after training (p<0.05). Average Cobb angle decreased to 23 degrees +/- 11 degrees (range 6 degrees -35 degrees). Four individuals showed reduction (>5 degrees) in their original curve, and 3 remained the same (+/-5 degrees). The strength training protocol significantly increased isometric rotational strength and scoliosis was stabilized short term.