Inheritance of Human Muscle Enzyme Adaptation to Isokinetic Strength Training

Abstract

Five monozygotic twin pairs were submitted to a 10-week isokinetic strength training program and biochemical characteristics measured before and after training to determine the role of heredity in skeletal muscle adaptation, while 5 unrelated sedentary subjects served as control group. Experimental subjects performed twice 3 series of 5 bilateral reciprocal alternating knee flexions and extensions at a velocity of 90 °/s 5 times per week. Before and after the training period, for each subject, the peak muscular torque output was measured at the same velocity and the vastus lateralis muscle was biopsied for biochemical determinations. No significant change was observed in the control group. Training increased peak muscular torque output by 24%. The activities of hexokinase, malate dehydrogenase and 3-hydroxyacyl CoA dehydrogenase also increased significantly by 28, 26 and 38%, respectively. Interindividual variations in the response of these variables to training were noted but these were shown to be independent of the genotype. No overall effect of training was observed for oxoglutarate dehydrogenase activity (OGDH). However, changes were seen in individual pairs of twins and these were in opposite directions in some pairs compared to others, thus explaining the absence of a general training effect. Significant intrapair resemblance in the training response was present for OGDH (r = 0.76), indicating that the sensitivity to isokinetic strength training for OGDH was highly variable, not random and probably genetically determined.

Hexokinase II protein content is a determinant of exercise endurance capacity in the mouse

“…Here we show that muscle HKII content and hence glucose phosphorylation capacity, is a critical determinant of exercise endurance capacity in C57BL/6J mice. These findings strongly suggest that the exercise training‐induced increase in HKII activity that has been reported previously (Barnard & Peter, 1969; Lamb et al 1969; Bylund et al 1977; Mandroukas et al 1984; Thibault et al 1986; Bigard et al 1991; Greiwe et al 1999) may be important to the increased exercise endurance of trained individuals. This is consistent with the observation that mice selected for increased running capacity have increased muscle hexokinase activity compared to control mice (Houle‐Leroy et al 2000).…”

ACE Genotype and the Muscle Hypertrophic and Strength Responses to Strength Training

“…Although the heritability of the adaptation of these muscle phenotypes to strength training (ST) has not been well studied, the adaptive response also appears to have a genetic component (26,27 The purpose of the present study was to investigate the association of ACE genotype with muscle phenotypes before and after ST in older men and women. Though the literature is inconclusive, the biological rationale suggests an advantage for the D allele with regard to muscle phenotypes; thus, we hypothesized that the D allele would be associated with higher values for muscle phenotypes before ST, and greater increases in muscle phenotypes in response to ST. As most studies have investigated only men, we investigated men and women to determine possible sex differences.…”

Genes and human elite athletic performance

“…Significant genetic influences have also been identified for measures of skeletal muscle strength and performance, including the response of oxoglutarate dehydrogenase activity to training (Thibault et al 1986), muscle adaptation to endurance exercise (Hamel et al 1986), vertical jump height as a measure of explosive power (Maes et al 1996), various measures of muscle strength and their response to training (Thomis et al 1998), anaerobic capacity and explosive power (Calvo et al 2002), average size of type I (slow oxidative) fibres in the sedentary state and maximal activity of energy production enzymes both in the sedentary state and in response to training (Rico-Sanz et al 2003b). The genetic contribution to variation in the relative proportions of skeletal muscle fibre types is estimated as lying between 40% and 50% (Simoneau and Bouchard 1995).…”