Comparison of an in-helmet temperature monitor system to rectal temperature during exercise.

Body temperature monitoring is crucial in helping to decrease the amount and severity of heat illnesses; however, a practical method of monitoring temperature is lacking. In response to the lack of a practical method of monitoring the temperature of athletes, Hothead Technologies developed a device (HOT), which continuously monitors an athlete's fluctuations in body temperature. HOT measures forehead temperature inside helmets. The purpose of this study was to compare HOT against rectal temperature (Trec). Male volunteers (n = 29, age = 23.5 ± 4.5 years, weight = 83.8 ± 10.4 kg, height = 180.1 ± 5.8 cm, body fat = 12.3 ± 4.5%) exercised on a treadmill at an intensity of 60-75% heart rate reserve (HRR) (wet bulb globe temperature [WBGT] = 28.7° C) until Trec reached 38.7° C. The correlation between Trec and HOT was 0.801 (R = 0.64, standard error of the estimate (SEE) = 0.25, p = 0.00). One reason for this relatively high correlation is the microclimate that HOT is monitoring. HOT is not affected by the external climate greatly because of its location in the helmet. Therefore, factors such as evaporation do not alter HOT temperature to a great degree. HOT was compared with Trec in a controlled setting, and the exercise used in this study was moderate aerobic exercise, very unlike that used in football. In a controlled laboratory setting, the relationship between HOT and Trec showed favorable correlations. However, in applied settings, helmets are repeatedly removed and replaced forcing HOT to equilibrate to forehead temperature every time the helmet is replaced. Therefore, future studies are needed to mimic how HOT will be used in field situations.

Acute heart rate, blood pressure, and RPE responses during super slow vs. traditional machine resistance training protocols using small muscle group exercises.

Acute cardiovascular and perceptual responses to Super Slow resistance training (SS) are not well understood. This study compared blood pressure (BP), heart rate (HR), and ratings of perceived exertion (RPE) between SS and traditional machine (TM) protocols. Participants (n = 20) completed three sessions of elbow flexion (EF) and knee extension (KE). Session 1 consisted of determining 1RM for EF and KE and a familiarization trial for the SS technique. Sessions 2 and 3 were counterbalanced, with subjects completing three sets of SS (10 seconds concentric, 5 seconds eccentric per rep, 40% 1RM) and TM (2 seconds concentric, 4 seconds eccentric per rep, 65% 1RM). Paramount resistance training equipment was used for both exercises. Peak HR was recorded for each set, with recovery HR taken between sets after 3 minutes of rest. Blood pressure was taken after 5 minutes of seated rest, after each set, before sets 2 and 3, and at 2 minutes post set 3. Ratings of perceived exertion for active musculature were obtained three times per set. Although systolic BP (SBP) and diastolic BP (DBP) responses were not significantly different between SS and TM for EF or KE, SBP (SS and TM combined) was significantly lower during EF and was significantly higher during KE than resting BP. Diastolic BP (SS and TM combined) was not significantly different from resting BP for EF or KE. Peak HR was significantly greater during TM (vs. SS) for EF and KE. Ratings of perceived exertion were also significantly greater during TM for EF and KE. Even though SBP was greater for SS and TM combined during KE, comparing SS and TM revealed minimal differences in BP. This suggests that, when performing small muscle group exercises with lighter weight at a slow speed, either SS or TM would be appropriate for individuals to whom strength training is not contraindicated.

Physical performance changes after unsupervised training during the autumn/spring semester break in competitive tennis players.

BACKGROUND: All competitive tennis players take time away from coaches throughout the year; however, little information is available as to the short-term physiological effect of these breaks. OBJECTIVE: The purpose of this investigation was to evaluate the impact of a 5 week off-campus structured, yet unsupervised, break from regular training in top collegiate tennis players. METHODS: A nationally ranked collegiate NCAA Division I male tennis team (n = 8) performed a test battery in December and again in January after a 5 week period of recommended, yet unsupervised, training. The tests performed were 5, 10 and 20 m sprints, spider agility test, medicine ball power throws, standing long jump, Wingate anaerobic power test, VO2max, push-up and sit-up test, grip strength and range of motion (ROM) measures (goniometer) of the shoulder, hip, hamstring and quadriceps. RESULTS: Paired t tests (p<0.05) showed significant decreases in mean (SEM) Wingate power measurements in Watts/kg (pre: 8.35 (0.19) w/kg ; post: 7.80 (0.24) w/kg ), minimum Wingate power (pre: 5.89 (0.27) w/kg; post: 5.10 (0.38) w/kg) and VO2max values (pre: 53.90 (1.11) ml/kg/min; post: 47.86 (1.54) ml/kg/min). A significant increase was seen in the athlete's fatigue index (pre: 44.26 (2.85)%; post: 51.41 (3.53)%), fastest 5 m (pre: 1.07 (0.03) s; post: 1.12 (0.02) s), 10 m (pre: 1.79 (0.03) s; post: 1.84 (0.04) s) and 20 m (pre: 3.07 (0.05) s; post: 3.13 (0.05) s) sprint times. No significant differences were seen for the other variables tested. CONCLUSIONS: These results suggest that a 5 week interruption of normal training can result in significant reductions in speed, power and aerobic capacity in competitive tennis players, likely owing to poor compliance with the prescribed training regimen. Therefore, coaches and trainers might benefit from techniques (eg, pre- and post-testing) requiring athletes' to have accountability for unsupervised workouts.

Effects of caffeine on repetitions to failure and ratings of perceived exertion during resistance training.

CONTEXT: Ergogenic effects of caffeine on aerobic or endurance exercise are well documented. Conversely, the ergogenic value of caffeine on high-intensity, primarily anaerobic performance is not well understood even though the proposed mechanisms of action for caffeine permit a strong theoretical basis for application to this type of exercise. PURPOSE: This study examined effects of caffeine (Ca) on number repetitions (reps), ratings of perceived exertion (RPE), and peak heart rate (PHR) during resistance-training exercise with reps performed to volitional failure. METHODS: Subjects (N = 17) were tested for 10-rep maximum in bench press (BP) and leg press (LP). In sessions 2 and 3, Ca (approximately 6 mg/kg) or placebo (Pl) was ingested 1 hr beforehand in a double-blind manner and counterbalanced order. Subjects performed 3 sets to failure (BP and LP) with reps, PHR, and RPE recorded each set. Repeated-measures ANOVAs, 2 (trial) x 3 (set), were used to analyze dependent measures with the Tukey honestly significant difference used when necessary as the post hoc test. RESULTS: In BP, no significant differences (Ca vs Pl) were observed (reps, RPE, PHR). During set 3 of LP training, Ca was associated with significantly higher reps (12.5 +/- 4.2 vs 9.9 +/- 2.6) and PHR (158.5 +/- 11.9 vs 151.8 +/- 13.2). No significant RPE differences were found during LP. CONCLUSIONS: The findings of similar RPE concurrent with higher reps suggest that caffeine can blunt pain responses, possibly delaying fatigue in high-intensity resistance training. Ergogenic effects might be limited to the later sets in a resistance-training session. Further research is warranted regarding ergogenic effects of caffeine during resistance training and potential mechanisms of action.