Turkish Journal of Medical Sciences




Although high muscle strength worsens the sense of force, it is unknown whether there is a relationship betweenthis deterioration and the underlying molecular mechanisms. This study examined the relationship between decreased force sense (FS)acuity and strength-related gene expressions.Materials and methods: Maximal voluntary isometric contraction (MVIC) and FS (50% MVIC) tests were performed on the kneejoints of twenty-two subjects. The expression analyses were evaluated by qRT-PCR in blood samples taken before, after MVIC, after 50%MVIC, and 15 min after the test.Results: MVIC and FS error values were significantly correlated with each other (r = .659, p = .001). The qRT-PCR analyses demonstratedthat the expressed mRNAs of the interleukin 6 (IL-6), alpha-actinin 3 (ACTN3), angiotensin-converting enzyme (ACE), brain-derivedneurotrophic factor (BDNF), and ciliary neurotrophic factor receptor (CNTFR) genes dramatically increased until 50% MVIC andsubsequently decreased 15 min after the exercise (p < .05). The muscle-specific creatine kinase (CKMM), myosin light chain kinase(MLCK), and G-protein β3 subunit (GNB3) genes reached their peak expression levels 30 min after MVIC (p < .05). ACE and ACTN3gene expression increased significantly in parallel with the increased FS error (p < .05). These gene expression fluctuations observed at50% MVIC and after the rest could be related to changes in cellular metabolism leading to fatigue.Conclusion: The time points of gene expression levels during exercise need to be considered. The force acuity of those whose maximalforce develops too much may deteriorate.


Proprioception, gene expression, qRT-PCR, muscle, strength

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