The work required to inflate and deflate the lung is governed by the equation: work = total intrapleural pressure × change in lung volume. For a given lung volume, it is therefore the internal pressures opposing inflation and deflation that dictate the efficiency of the lung. Three main components contribute to intrapleural pressure other than [...]
Insulin increases the uptake of glucose by the muscles, promotes the synthesis of glycogen, inhibits lipolysis and increases lipid synthesis; therefore it has been speculated that age-dependent changes in blood insulin concentration might influence metabolic characteristics. Supporting data are, however, not convincing. In one of the most comprehensive studies, Wirth et al (1978) determined the [...]
Typically, during childhood and puberty, strength increases coincide with changes in fat-free mass (FFM). Moderate to strong correlations have been found for knee extension and flexion torque versus FFM in 8- to 13-year-old wrestlers (Housh et al 1996). However, further studies have reported age-related increases in torque per FFM for knee extensors and elbow extensors [...]
Muscle strength is a multifaceted, performance-related fitness component that is underpinned by muscular, neural and mechanical factors. The complex interaction of these components makes the study of the increase in muscle strength during growth and maturation challenging. The origins of the diversity in muscularity in adults occur early in fetal development, at approximately the fifth [...]
There has been considerable debate in both the adult and paediatric literature concerning the numerical value of the mass exponent and whether there is a ‘true’ mass exponent that might provide a universal alternative to simple per body mass scaling at least for maximal power outputs. The two values most frequently discussed are 0.67 and [...]