The validity and reliability of a novel mobile app to measure agility performance in the physically active youth population

Agility is a key component of physical fitness in adolescents. However, the measurement of this variable is usually complex, requiring high cost instruments and complex software. To test the validity and reliability of a novel iPhone app (Lap Tracker Auto-timer) to measure agility performance among adolescents. Twenty-four physically active adolescents (15.7 ± 2.3 years old) participated in two testing sessions (separated by 7 days). They performed three 4 x 10 m agility test trials measured by Photocell or the iPhone app. The correlation analysis revealed high validity (r = .92; 95% confidence interval [CI] = .88 – .95), with a standard error of the estimate of 0.56 s (p < 0.001). The coefficient of variation (CV; 0.09) and intraclass correlation coefficient (ICC; .93; 95% CI = .85 – .97) showed an acceptable reliability. This study demonstrated that the iPhone App Lap Tracker Auto-timer could be a valid, reliable and low-cost tool to evaluate agility performance in adolescents. However, more studies are required to guarantee the utility of this app.

The acute effects of a dynamic warm-up including hip mobility exercises on sprint, agility and vertical jump performance

The purpose of this study was to examine the acute effects of a dynamic warm-up including hip mobility exercises on sprint, agility and vertical jump performance. Twenty well trained male collegiate athletes (age = 20 ± 1.1 years; height = 178.3 ± 8.8 m; body weight = 72 ± 5.6 kg) volunteered for the study. All subjects completed two individual testing sessions on two non-consecutive days. On the first trial day, after 15 minutes of a simple dynamic warm-up, 30-m sprint test, Illinois agility test and countermovement jump test were performed at the control condition. On the second trial day addition to dynamic warm-up, subjects performed 6 hip mobility (6 min) exercises before tests. A paired samples t-test revealed a significant difference (p = 0.013) on sprint performance when comparing simple dynamic warm-up with a dynamic warm-up including hip mobility exercises. But no significant difference was found for agility (p = 0.071) and jump performances (p = 0.823). It can, therefore, be concluded that has a significant effect on sprinting performance whereas it has no significant effect on agility and vertical jump performance.

The influence of auditory information on performance in table tennis

It is well-known that visual information is essential for anticipation in table tennis but it not clarified whether auditory cues are also used. Therefore, we performed two in-situ studies, in which novices (study A) and advanced players (study B) responded to strokes of a real opponent or a ball machine by returning with forehand counters (study A) and forehand top spins (study B) to a given target area on the table. We assessed the parameters “hit quality” and “subjective effort”. In study A, we provided four conditions: normal, a noise-cancelling headphone and earplugs to dampen auditory information, other noise-cancelling headphones and earplugs to remove almost all environmental sounds, and the same head-phones with additional bright noise to remove all sounds. In study B, we performed three tests (irregular play and regular play with an opponent and response to regular balls of a ball machine) under two conditions: normal and noise-cancelling headphones with the additional bright noise. In both studies, no significant differences between all conditions for “hit quality” and “subjective effort” (all p>0.05) were found. We conclude that auditory information, as well as their volume, have no influence on the hit quality in table tennis for novices and advanced players.