GROUPEMENT D’ISOCINETISME BELGE ET LUXEMBOURGEOIS.
5e Journée Belge
Campus ERASME - Bruxelles
Isocinétisme et techniques d’évaluation de la fonction musculaire
EFFECT OF PREVENTIVE PATELLOFEMORAL BRACING ON MUSCLE STRENGTH – A PROSPECTIVE STUDY.
D. Van Tiggelen (1,2); E. Witvrouw (2); P. Coorevits (2);
(1) Belgian Defense, Hospital Center Base Queen Astrid, Dept Rehabilitation & Physiotherapy, Bruynstraat 2, 1120 Brussels (B)
(2) Ghent University, Faculty of Medicine & Health Sciences, Dept Physiotherapy & Rehabilitation, De Pintelaan 185, 9000 Gent (B)
A previous study (1) showed a diminished incidence of anterior knee pain (AKP) in recruits wearing a patellofemoral brace during strenuous training. Recruits who developed AKP during Basic Military Training (BMT) have a poor quadriceps muscle function prior to the start of the BMT (2). The results of this and other observations (3) support the concept that a good quadriceps muscle function is the cornerstone to avoid or recover from AKP. In this study the influence of patellofemoral bracing on the quadriceps strength is investigated.
164 Male recruits, without history of knee pain, volunteered for this study. Each volunteer underwent an isokinetic test of the quadriceps muscle prior to the start of a 6-week BMT. Every third recruit received a pair of patellofemoral braces (On-Track, DJ Ortho) to put on during physical activities. Chi² statistics was used to compare the number of AKP patients in braced and non-braced recruits. Recruits who developed anterior knee pain were excluded (n = 40) in both groups. In the unaffected subjects a 2-way ANOVA with "before" and "after" the BMT as within subject factor and "braced" _versus "non-braced" as between subject factor was performed.
Baseline characteristics of the quadriceps muscle torque were not significantly different between the braced and non-braced groups (p>0.05). The Chi² test (Fisher Exact) revealed significantly less AKP patients in the braced group versus the non-braced one (p = 0.026). By performing the ANOVA, no interaction between the factors at 240°/s was observed. On the other hand, we observed a decrease in quadriceps muscle absolute and relative peak torque at 60°/s. This decrease is only significant in the non-braced subjects (table 1) DISCUSSION: Strenuous training affects the quadriceps muscle function even in asymptomatic subjects. Since this is only observed at slow isokinetic speeds (60°/s), it's probably due to tissue irritation leading to reflex inhibition. We observe a positive influence of the patellofemoral brace on the quadriceps muscle function.
Further research on the exact underlying mechanism(s) should give more insights. Changes in the position of the patella (5), proprioceptive improvements (6,7), altered muscular recruitment patterns (8), or the influence of compression on the inhibition are potential mechanisms, which need more investigations.
Regarding the results of this study, the preservation of the quadriceps muscle function is one of the suggested mechanisms of patellofemoral bracing.
1. Van Tiggelen D, Witvrouw E, Roget Ph, Cambier D, Danneels L, Verdonk R. Knee Surg Sports Traumatol Arthrosc. Sep; 12(5): 434-439, 2004.
2. Van Tiggelen D, Witvrouw E, Coorevits P, Croisier JL, Roget Ph. Isokin Exerc Sci 12: 223-228, 2004.
3. Powers CM, Perry J, Hsu A, Hislop HJ. Phys Ther 77(10): 1063-1075, 1997.
4. Witvrouw E, Lysens R, Bellemans J, Cambier D, Vanderstraeten G. AJSM 28(4), 2000.
5. Powers CM, Ward SR, Chen YJ, Chan LD, Terk MR. AJSM 32(1): 224-231, 2004.
6. Perlau R, Frank C, Fick G. AJSM 23(2): 251-255, 1995.
7. Birmingham TB, Inglis JT, Kramer JF, Vandervoort AA. MSSE 32(2), 2000.
8. Gilleard W, McConnell J, Parsons D. Phys Ther 78(1), 1998.