Differences between the Grab Start and Track Start in Collegiate Swimmers

International Journal of Exercise Science 10(4): 515-521, 2017. The purpose of this investigation was to determine which foot stance, the track start (TS) or the grab start (GS), is most beneficial for competitive swimmers. Seven male and eight female collegiate swimmers participated in this study. The average participant age was 20.1 ± 1.13 years while the average years of competitive swimming experience was 10.8 ± 3.36 years. Participants performed three TS and three GS stances consecutively. Distance markers were placed on the side of the pool to determine where each swimmer entered the water. Video analysis was used to determine the following factors: start phase time, flight phase time, flight distance, horizontal entrance velocity, and entrance angle. Prior to participating in the study, swimmers completed a brief survey regarding age and competitive swimming experience, and researchers measured each participant’s height and weight. A paired sample T-test was used to determine significant differences between the GS and TS. The results indicated that the TS foot stance resulted in a shorter start phase time (0.76 ± 0.07 s vs. 0.88 ± 0.10 s; P \u3c 0.001), a shorter flight phase time (0.81 ± 0.08 vs. 0.95 ± 0.07; P \u3c 0.001), and a greater horizontal entrance velocity (3.56 ± 0.51 m/s vs. 3.10 ± 0.41 m/s; P \u3c 0.001). The GS allowed swimmers to travel further in the air (2.96 ± 0.43 m vs. 2.88 ± 0.41 m; P = 0.013). The TS entrance angle was significantly shallower than the GS entrance angle (36.98 ± 3.17° vs. 38.53 ± 3.81°; P = 0.004). Based on the results, the TS foot stance provides swimmers with the greatest advantage

Thermoregulatory Adaptations following Sprint Interval Training

Traditional endurance training typically involves weeks of long-duration (60–90 min) exercise performed at a moderate to vigorous intensity. An alternative paradigm, sprint interval training, is characterized by multiple bouts of short-duration, high-intensity exercise. Similar fitness benefits from the two paradigms have been demonstrated, but whether sprint interval training—like traditional endurance training—induces heat acclimation remains unclear. Purpose To test the hypothesis that sprint interval training performed over six sessions results in measureable thermoregulatory and cardiovascular adaptations consistent with heat acclimation. Methods Seven untrained men [mean ± SD, 13 ± 5% body fat, 22 ± 3 y, 3.1 ± 0.3 L/min peak oxygen uptake (V̇O2peak)] performed 6 sprint interval training sessions over 12 days with 48­–72 h between sessions. Sessions consisted of 4–6 thirty-second Wingate Anaerobic Tests separated by ~4 min. Before and after the two-week training protocol, participants cycled for 30 min at 65% V̇O2peak in 25 °C to assess the effects of sprint interval training on heat acclimation. Results Main outcome variables (onset of sweating, sweat sensitivity, heart rate at end of exercise, percent change in plasma volume, and core temperature change from pre- to post-exercise) were not different from pre- to post-training (all p \u3e 0.05). Conclusion Two weeks of sprint interval training performed under the conditions specified does not result in heat acclimation

Performance and perceptual responses of collegiate female soccer players to a practical external and internal cooling protocol

International Journal of Exercise Science 8(4): 331-340, 2015. This study examined practical pre- and mid practice cooling interventions on running performance, perceived exertion (RPE), and thermal sensation (TS) during soccer. During two formal pre-season practices female, NCAA Division II soccer players participated in three, 15 min scrimmage bouts followed by a 4th 10 min bout. Following the 1st, 2nd, and 3rd bouts, 8 field position players completed competitive sets of two, 30 yard sprints against other team members with time recorded between 5 and 30 yards. After the 4th bout, players completed an indoor shuttle running beep test (BT). In the treatment group (COOL) ice towels (IT) were applied to the head and neck regions and draped across both legs for 10 min following a standardized warm-up and for 10 min during a 15 min break between the 2nd and 3rd scrimmage sessions. Sport beverage slurries (350 mL; -0.3 °C, ~6% carbohydrate) were also served during IT cooling for COOL; while the control (CON) received no IT and drank the same ,uncooled sport beverage. No main effect was found for sprint performance (COOL = 3.55 ± 0.16 s; CON = 3.51 ± 0.07 s; P = 0.51) or numbers of reps completed in the BT (COOL = 17.6 ± 5.6; CON = 17.3 ± 6.0; P = 0.88). RPE did not differ following any performance test, but TS was lower following the 3rd sprint bout (P = 0.04) and the BT (P = 0.005) for COOL. COOL promoted lower TS, but had no effect on performance

Acute Effect of Lower-Body Vibration as a Recovery Method After Fatiguing Exercise

The purpose of this study was to compare three recovery methods: control (CON), lower-body vibration (LBV) and LBV+ local muscle cooling (LBVC) on lower-body performance, perceived recovery, and muscle soreness. Physically active male volunteers (n=8) in a repeated-measures, counterbalanced design, completed three sets of squats to fatigue, each recovery treatment, and two Wingate Anaerobic Tests. Rating of perceived exertion (RPE), and heart rate (HR) were measured after fatiguing exercise, recovery treatment and Wingate Anaerobic tests. Peak and mean power, fatigue index, Delayed Onset Muscle Soreness (DOMS), and comfort levels were compared between each treatment. In Wingate 1, no significant differences (p=0.42) were found among CON, LBV, or LBVC regarding peak power (1119±239, 1097±225, and 1146±260 W, respectively), mean power (p=0.32), or fatigue index (p=0.47). In Wingate 2, no significant (p=0.17) differences were found among CON, LBV, or LBVC regarding peak power (1042±228, 1078±233, and 1110±268 W, respectively), mean power (p=0.38), or fatigue index (p=0.15). A significantly better (p=0.01) perceived recovery was observed after LBV (6±1) and LBVC (6±1) compared to CON (4±1). The study findings support psychological but not performance enhancing benefits after the use of LBV and LBVC as recovery methods

Effect of Half Time Cooling on Thermoregulatory Responses and Soccer-Specific Performance Tests

This study examined two active coolings (forearm and hand cooling, and neck cooling) during a simulated half-time recovery on thermoregulatory responses and subsequent soccer-specific exercise performance. Following a 45-min treadmill run in the heat, participants (N=7) undertook 15-min recovery with either passive cooling, forearm and hand cooling, or neck cooling in a simulated cooled locker room environment. After the recovery, participants performed a 6×15-m sprint test and Yo-Yo Intermittent Recovery Level 1 test (YYIR1) in a temperate environment. During the 15-min recovery, rectal temperature fell significantly (p<0.05). Neither active coolings induced further reduction in rectal temperature compared to passive cooling. No effect of active coolings was found in repeated sprint test. However, neck cooling reduced (p<0.05) the thermal sensation (TS) compared to passive cooling during the 15-min recovery. Active coolings attenuated (p<0.05) the sweat rate compared to passive cooling: 1.2±0.3 l•h-1 vs. 0.8±0.1 l•h-1 vs. 0.8±0.3 l•h-1, for passive cooling, forearm and hand cooling, and neck cooling, respectively. For passive cooling, elevated sweat rate resulted in higher (p<0.05) dehydration (2.1±0.3%) compared to neck cooling (1.5±0.3%) and forearm and hand cooling (1.4±0.3%). YYIR1 was improved (p<0.05) following forearm and hand cooling (869±320 m) and neck cooling (814±328 m) compared to passive cooling (654±311 m). Neck cooling (4.6±0.6) reduced (p=0.03) the session TS compared to passive cooling (5.3±0.5). These results suggest that active coolings effectively improved comfort and sweating response, which delayed exercise-heat induced performance diminish during a second bout of exercise