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 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.