(66) DIFFERENCES IN MUSCLE PERFORMANCE BETWEEN STRENGTH ATHLETES, PHYSIQUE COMPETITORS, AND UNTRAINED INDIVIDUALS

Chronic resistance training leads to a remarkable increase in muscle strength output. The muscle strength characteristics may differ depending on the strength training regimen performed. Strength athletes, such as powerlifters and weightlifters, focus on increasing maximal muscle strength, while physique athletes aim to increase muscle size. This study examined the muscle strength characteristics of men and women strength and physique athletes with a cross-sectional study design.

Twelve strength (SA, 6 men, 6 women) and 13 physique athletes (PA, 7 men, 6 women) with about 7 years of drug-free competition history volunteered for the study. They were all national best and/or top-level competitors at the European Championship level. Age-matched untrained lean individuals were recruited as a control group (CONT, 7 men, 7 women). Body fat % was determined by bioimpedance, and fat-free mass index (FFMI) was calculated. Maximal isometric knee extension torque (ISOM) was measured. One repetition maximum (1RM) in barbell biceps curl and horizontal leg press device was assessed. FFMI adjusted ratio between ISOM and leg press 1RM was calculated. The cross-sectional area (CSA) of the biceps brachii and vastus lateralis (VL) was measured by ultrasound. From VL, the fascicle pennation angle was measured, and physiological CSA (pCSA) was calculated.

In both men and women, FFMI, VL CSA, maximal knee extension torque, and 1RM in leg press were greater (p < 0.05) in SA and PA than in CONT. In men, biceps curl 1RM was greater (p < 0.05) in SA and PA than in CONT, and biceps CSA and VL pCSA were greater (p< 0.05) in PA than in CONT. Biceps 1RM normalized to CSA was lower (p< 0.05) in PA than in SA in men, and lower (p< 0.05) in PA than in CONT in women. In women, biceps 1RM and CSA, and leg press 1RM normalized to VL pCSA were greater (p< 0.05), and the maximal knee extension torque ratio to leg press 1RM was lower (p< 0.05) in PA than in CONT.

As expected, FFMI, maximal muscle strength and size were generally greater in chronically resistance-trained SA and PA men and women than in their untrained peers. Interestingly, the strength-to-size ratio in the biceps was lower in PA, indicating training specificity as their biceps training has focused on maximizing muscle hypertrophy. It is also essential, however, to point out what was not found in this study. In general, no differences were observed between the groups in isometric to dynamic strength ratio. Thus, CONT did not show a dynamic strength deficit compared to SA and PA, even though their training includes a lot of dynamic muscle strength exercises.   

Specific strength output in knee extensors, determined here as a maximal knee extension torque adjusted with VL pCSA, was similar between the groups. This suggests that the strength training performed by SA and PA has not induced functional changes in the contractile machinery of the muscle and, thus, in the production of muscle force. That is, their muscle strength was mainly determined by muscle size. Although differences in strength training practices between SA and PA are obvious, practically no differences were observed between them in the present simple kind of laboratory strength measurements, such as knee extension, leg press, and biceps curl. Thus, SA and PA are mainly separated by sports-specific motor skills and physical aesthetics rather than muscular strength output as such.

 

Acknowledgements: None