Showing papers by "Alun G. Williams published in 2004"
TL;DR: Data suggest that common genetic variation in the B(2)R is associated with efficiency of skeletal muscle contraction and with distance event of elite track athletes and that at least part of the associations of ACE and fitness phenotypes is through elevation of kinin activity.
Abstract: Accumulating evidence suggests that athletic performance is strongly influenced by genetic variation. One such locus of influence is the gene for angiotensin-I converting enzyme (ACE), which exhibi...
113 citations
TL;DR: These are the first objective data on which to prescribe training for load carriage on an individual basis and stronger subjects with lower endurance responded better to Circuits.
Abstract: To explore the possibility of training diagnosis
for a 3.2-km loaded march with a 25 kg load, 50 men
trained for 10 weeks using either running, marching, and endurance-
based circuit training (Circuits), or running, marching,
and resistance training (Resistance). The march was performed
before and after training, and other measurements related to
loaded marching were conducted before training only. Each
group was ranked by improvement in the loaded march, and
divided into significantly different subgroups of 'good' and 'poor'
responders (improvements of approximately 20% vs. 10%). For
Circuits, there were significant differences between good and
poor responders to training in the pretraining ratios of shuttle
run: isometric lift strength (p 5 0.031) and shuttle run: isometric
back extension strength (p 5 0.033). Stronger subjects with lower
endurance responded better to Circuits. Resistance tended to
show the opposite effect (p , 0.2). These are the first objective
data on which to prescribe training for load carriage on an individual
basis.
22 citations
TL;DR: The results suggest that acute exercise and glucose ingestion interventions as used here do not affect circulating ACE activity, and are an early step in illuminating the relationships between ACE activity and various exercise parameters.
Abstract: Angiotensin-converting enzyme (ACE) activity has been suggested as a determinant of some exercise phenotypes via some studies that have associated the ACE gene with exercise performance, although several studies provide conflicting evidence regarding the influence of the ACE gene. The relationships between ACE phenotype (ACE activity) and various exercise parameters should also be examined. An early step in this process is to determine whether common environmental stimuli such as exercise and diet have acute effects on ACE activity. In this study, the acute effects of aerobic exercise, resistance exercise and glucose ingestion on circulating ACE activity were examined. On three separate occasions, 20 healthy adult volunteers (9 female and 11 male) performed 20 min of submaximal cycle exercise at 70–80% of maximal heart rate, four sets of ten repetitions of unilateral leg extension resistance exercise at ten-repetition maximum load, or ingested 1 g kg−1 glucose. Circulating ACE activity was assessed for 1 h after each intervention using a modified fluorometric method. Pre-intervention ACE activity remained remarkably stable across test days (difference ≤1.8%). Furthermore, there was no significant change in circulating ACE activity following any of the interventions (difference from pre-intervention values ≤6.8% when unadjusted for plasma volume changes, ≤4.5% when adjusted for plasma volume changes). These results suggest that acute exercise and glucose ingestion interventions as used here do not affect circulating ACE activity. These findings are an early step in illuminating the relationships between ACE activity and various exercise parameters.
6 citations