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Aim: HIIT (Hit Intensity Interval Training) consists of low volume, but increased intensity in a short period of time followed by a relative recovery period, which can be active or passive. In addition, the implementation of rest recovery intervals between high intensity short duration activities is optimal for maintaining exercise functionality and has been shown to improve overall exercise performance. The objective of this study was to evaluate the effects of a long and short rest recovery intervention on blood lactate accumulation between multiple sets of sprinting activities. Methods: Forty students aged 21.9 ± 0.3 years participated in the high intensity sprinting sessions. Subjects were randomly assigned into recovery conditions (modality x duration) which was one of four groups: active recovery for 10 minutes (AR10), active recovery for 5 minutes (AR5), passive recovery for 10 minutes (PR10), or passive recovery for 5 minutes (PR5). Blood lactate, heart rate, RPE, and sprint time were collected after each sprint (3-repeats) to assess performance changes. Differences in dependent variables were assessed using two-way repeated measures ANOVA. Results: A statistically significant difference was observed between the AR10 and PR5 intervention groups for blood lactate concentrations at 5-minute post exercise (p = .034) and for the mean lactate values across trails (p = .031). Conclusions: Active recovery could be more beneficial for lactate clearance when compared to passive recovery during highintensity interval training and longer recovery periods incorporating physical activity may have a greater benefit of optimizing exercise performance during high intensity power activities. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the validity of whole body percent fat (%BF) and segmental fat-free mass (FFM) using multi-frequency bioelectrical impedance analysis (MF-BIA) and dual-energy x-ray absorptiometry (DEXA) in college-aged adults. Sixty-two participants male ( n = 32) and female ( n = 30) completed MF-BIA and DEXA measurements following established pre-test guidelines. %BF and segmental FFM (right arm, left arm, trunk, right leg, and left leg) were collected and analyzed. The MF-BIA significantly ( p < 0.05) underestimated %BF for all participants, females, and males compared to DEXA. In addition, MF-BIA significantly ( p < 0.05) underestimated FFM in the arms and legs in all participants and males with the exception of the left arm in all subjects while significantly overestimating FFM in the trunk. In females, the MF-BIA overestimated FFM in the arms and trunk while significantly ( p < 0.05) underestimating FFM in the legs. Difference plots also indicated that the underestimation of FFM from MF-BIA in the arms and legs increased as the amount of FFM increased. Thus, our findings suggested that the MF-BIA may not be accurate for measuring whole %BF and segmental FFM in the college-aged population.