Browsing Sport and Exercise Sciences by Publisher "National Strength and Conditioning Association"
Now showing items 1-4 of 4
A comparison of the FitroDyne and GymAware rotary encoders for quantifying peak and mean velocity during traditional multi-jointed exercisesThe FitroDyne and GymAware rotary encoders are being increasingly used in resistance training to monitor movement velocity, but how closely their velocity outcomes agree is unknown. Consequently, this study aimed to determine the level of agreement between the FitroDyne and GymAware for the assessment of movement velocity in three resistance training exercises. Fifteen males performed three repetitions of bench press, back squat and bent-over-row exercises at 10% one repetition maximum increments (from 20 to 80%). For each repetition, the FitroDyne and GymAware recorded peak and mean barbell velocity (cm.s-1). Though strongly correlated (r = 0.79 to 1.00), peak velocity values for the GymAware were significantly lower than the FitroDyne for all exercises and loads. Importantly, the random errors between the devices, quantified via Bland and Altman's 95% limits of agreement, were unacceptable, ranging from ± 3.8 to 25.9 cm.s-1. Differences in mean velocity were smaller (and non-significant for most comparisons) and highly correlated (r = 0.86 to 1.00) between devices. Notwithstanding smaller random errors than for the peak values, mean values still reflected poor agreement (random errors between ± 2.1 to 12.0 cm.s-1). These findings suggest that the FitroDyne and GymAware cannot record peak or mean velocity with acceptable agreement, and should neither be employed interchangeably nor their data compared.
The effects of a cycling warm-up including high-intensity heavy-resistance conditioning contractions on subsequent 4 km time trial performancePrior exercise has been shown to improve subsequent performance via different mechanisms. Sport-specific conditioning contractions can be used to exploit the 'post-activation potentiation' (PAP) phenomenon to enhance performance although this has rarely been investigated in short endurance events. The aim of this study was to compare a cycling warm-up with PAP-inducing conditioning contractions (CW) with a moderate intensity warm-up (MW) on performance and physiological outcomes of 4 km time trial. Ten well-trained male endurance cyclists (V[Combining Dot Above]O2max 65.3 +/- 5.6 ml[middle dot]kg-1[middle dot]min-1) performed two 4 km cycling time trials following a 5-minute recovery after a warm-up at 60% of V[Combining Dot Above]O2max for 6.5-minutes (MW), and a warm-up with conditioning contractions (CW) consisting of 5 minutes at 60% of V[Combining Dot Above]O2max then 3 x 10-seconds at 70% of peak power interspersed with 30-seconds recovery. Blood lactate concentrations were measured before and after time trial. Expired gases were analysed along with time, power output (PO), and peak forces over each 500 m split. Following CW, mean completion time was reduced (1.7 +/- 3.5 s p > 0.05), PO increased (5.1 +/- 10.5 W p > 0.05) as did peak force per pedal stroke (5.7 +/- 11 N p > 0.05) when compared to MW. V[Combining Dot Above]O2 increased (1.4 +/- 1.6 ml[middle dot]kg-1[middle dot]min-1 p < 0.05) following CW, whilst RER decreased (0.05 +/- 0.02 p < 0.05). Physiological and performance differences following CW were greatest over the first 1500 m of the trials. The results suggest a PAP-inducing warm-up alters V[Combining Dot Above]O2 kinetics and can lead to performance improvements in short endurance cycling but work and recovery durations should be optimised for each athlete.
The effects of Bodymax high-repetition resistance training on measures of body composition and muscular strength in active adult womenThe purpose of this study was to investigate the effects of a light, high-repetition resistance-training program on skinfold thicknesses and muscular strength in women. Thirty-nine active women (mean age 38.64 +/- 4.97 years) were randomly placed into a resistance-training group (RT; n = 20) or a control group (CG; n = 19). The RT group performed a resistance-training program called Bodymax for 1 hour, 3 d.wk(-1), which incorporated the use of variable free weights and high repetitions in a group setting. The CG group continued its customary aerobic training for 1 hour 3 d.wk(-1). Five skinfold and 7 muscular strength measures were determined pretraining and after 12 weeks of training. Sum of skinfolds decreased (-17 mm; p < 0.004) and muscular strength increased (+57.4 kg; p < 0.004) in the RT group. Effect sizes for individual skinfold sites and strength measures were "medium" and "high," respectively. Bodymax is an effective resistance-training program for reducing skinfold thickness and increasing muscular strength in active women. Therefore, women with a similar or lower-activity status should consider incorporating such training into their regular fitness programs.
The reliability and validity of short-distance sprint performance assessed on a nonmotorized treadmillThis study examined the interday and intraday reliabilities and validities of various sprint performance variables on a nonmotorized treadmill (NMT) over distances of 10, 20, and 30 metres.