Affiliations: Department of Medical Rehabilitation, College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
Correspondence:
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Corresponding author: Ayodele Teslim Onigbinde, Department of Medical Rehabilitation, College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. E-mail:[email protected]
Abstract: PURPOSE: The primary objective of this study was to establish if
there would be inter-limb crossing of strength from trained quadriceps
muscles of unaffected limb to the untrained homologous group of muscles in
subjects with knee osteoarthritis. METHODS: Twenty-one patients with knee osteoarthritis were
recruited for the study. The affected knee was not trained while the
unaffected quadriceps group of muscles was trained
for 6 weeks using isometric contraction exercises. The patients sat on a
quadricep bench with knee flexed to 90° as starting position. An ankle
strap was used to fasten the required weight for isometric training at the
lower one-third of the unaffected limb. Each patient extended the unaffected
knee until the leg was fully straightened, maintaining quadriceps isometric
contraction for 3 to 5 seconds; and then slowly returned to the starting
position; 12 repetitions and 3 sets were performed thrice a week for 6
weeks. The peak isometric quadricep strengths of both limbs were quantified
with spring balance at baseline and after 6 weeks. During quantification,
all the patients were verbally motivated to achieve maximum voluntary
contraction at extension. The data were analyzed using descriptive
statistics of mean, standard deviation and percentages. Parametric
inferential statistics of dependent t-test (paired) was used to compare the
pre and post values obtained. RESULTS: The peak isometric quadriceps strength of the affected
limb with knee osteoarthritis without training at baseline was 132.67 ±
42.26 N while at the 6th week it was 159.30 ± 49.33 N showing a
significant increase of 20% (p = 0.001). For the trained unaffected knee,
at onset and at 6th week, the peak isometric quadricep strengths were
158.83 ± 43.28 N and 192.00 ± 47.31 N respectively. There was
significant increase of 21% in the quadriceps muscle strength of the
unaffected knee after training (p = 0.001). However, there was no
significant difference in the increments observed between the peak isometric
quadriceps strengths of both limbs (p = 0.06). CONCLUSION: We
concluded that there was cross training effect on the contralateral
quadriceps muscle when only the ipsilateral (unaffected) homologous muscle
was strengthened.
Keywords: Osteoarthritis, cross training effects, repetition maximum, quadriceps muscle strength
