The primary purpose of this paper was to provide insight into the effect of different training methods on sprinting time in male youth aged 8-18 years. Specific and nonspecific training methods were identified, the participants of the five teen studies categorized into pre, mid- and postpeak height velocity and effect sizes and percent changes calculated for each training method were appropriate. Plyometric training had the most effect on sprint times in pre- and midpeak height velocity participants, while combined training methods were the most efficient in postpeak height velocity participants. However, it is difficult to quantify the effects of different training methods due to the limited knowledge in this area e.g., resisted training on pre-PHV participants. Furthermore, it may be worthwhile to investigate additional variables (i.e., stride length, stride frequency, horizontal force), to better determine effect of training methods in different maturity statuses, the development of sprinting and possible stages where individual development can be optimized by training.

The purpose of this study was to quantify the inter-session reliability of force-velocity-power profiling and estimated maximal strength in youth. Thirty-six males (11-15 years old) performed a ballistic supine leg press test at five randomized loads (80%, 100%, 120%, 140%, and 160% body mass) on three separate occasions. Peak and mean force, power, velocity, and peak displacement were collected with a linear position transducer attached to the weight stack. Mean values at each load were used to calculate different regression lines and estimate maximal strength, force, velocity, and power. All variables were found reliable (change in the mean [CIM] = - 1 to 14%; coefficient of variation [CV] = 3-18%; intraclass correlation coefficient [ICC] = 0.74-0.99), but were likely to benefit from a familiarization, apart from the unreliable maximal force/velocity ratio (CIM = 0-3%; CV = 23-25%; ICC = 0.35-0.54) and load at maximal power (CIM = - 1 to 2%; CV = 10-13%; ICC = 0.26-0.61). Isoinertial force-velocity-power profiling and maximal strength in youth can be assessed after a familiarization session. Such profiling may provide valuable insight into neuromuscular capabilities during growth and maturation and may be used to monitor specific training adaptations.

The ability to judge distance and navigate through an environment with obstacles using a device which audifies ultrasound was shown to be better than using auditory echolocation, but not as effective as vision. This device will allow individuals with visual impairments to better detect and avoid environmental obstacles.

The purpose of this study was to assess the possible contribution of 1RM leg-press strength and jump peak power to 20-m sprint time in young athletes in three maturity groups based on age relative to predicted age of peak height velocity (PHV): Pre (- 2.5 to -1.0 years; n=25), Mid (- 1.0 to 0.5 years; n=26) and Post (0.5 to 2.0 years; n=15). Allometric scaling factors, representing percent difference in 20-m time per percent difference in strength and peak power, were derived by linear regression and were similar in the three maturity groups (-0.16%/% and -0.20%/% for strength and peak power, respectively). The moderate increase in sprint performance Pre to Mid PHV (5.7%) reduced to small (1.9%) and trivial but unclear (0.9%) magnitudes after adjustment for 1RM and peak power, while the moderate increase Mid to Post PHV (4.6%) were still moderate (3.4 and 3.0%) after adjustment. Thus percent differences in strength or power explained most of the maturity-related improvements in sprint performance before PHV age but only some improvements after PHV age. Factors in addition to strength and power should be identified and monitored for development of speed in athletes during puberty.

This paper discusses the development of a prototype design of an auditory interface for the visually impaired based on the work domain analysis of ecological interface design. Secondary mobility devices have been developed to increase preview distances in addition to a long cane, but these have gained limited acceptance. These devices lack an easily interpreted interface. An interface design that provides the user with sufficient preview to avoid obstacles and plan a path among obstacles is presented