Deception of Ambient Temperature Does Not Elicit Performance Benefits During a 5 km Run in Hot, Humid Conditions.

Hanson, NJ, Carriveau, DM, Morgan, HE, Smith, AR, Michael, TJ, and Miller, MG. Deception of ambient temperature does not elicit performance benefits during a 5 km run in hot, humid conditions. J Strength Cond Res 32(8): 2250-2257, 2018-The purpose of this study was to investigate the effect of deception of ambient temperature on 5 km performance in recreational runners. Eleven participants (6 men, 5 women) each performed three 5 km runs in a random order consisting of a control trial (CON) in temperate conditions (21° C, 43% RH), a hot humid trial (HOT; 31° C, 65% RH) and a deception trial (DEC; 31° C, 65% RH), where participants were told it was 5° C lower than it actually was. Overall completion time was recorded at the end of trials; thermal sensation (TS), rating of perceived exertion (RPE), and core temperature (TC) were recorded each kilometer. Participants completed the 5 km run faster in the CON condition (23:18 ± 2:05; mean ± SD) compared with DEC (p = 0.005) and HOT (p = 0.014). There was no difference in completion time (p = 0.554) between DEC (25:11 ± 2:41) and HOT (24:25 ± 2:47). Similarly, TS was lower in the CON condition (5.7 ± 0.2) compared with DEC and HOT (p < 0.001 and p = 0.016, respectively) and no differences were seen between the DEC (6.4 ± 0.2) and HOT (6.5 ± 0.2) conditions. No differences in RPE (p = 0.115) or rise in TC (p = 0.289) were seen between the 3 conditions. Deception of the environmental conditions did not positively affect 5 km running performance, and no differences were seen in physiological or psychological variables.

Over-the-counter performance enhancing mouthguards are unable to decrease blood lactate and improve power output during a Wingate anaerobic test (WAnT).

BACKGROUND/OBJECTIVE: Mouthguards are the primary mode of protection against maxillofacial injuries in contact sports, but recent research has also linked performance enhancement to this piece of equipment. The purpose of this study was to test the claims of the Under Armour ArmourBite (UAAB) mouthguard to decrease blood lactate concentration ([BL]) and increase power when compared to a generic over-the-counter mouthguard (OTC) and no mouthguard (NOMG) during an anaerobic performance test. METHODS: Seventeen recreationally active males (23.4 ±â€¯2.7 years; 179.6 ±â€¯7.4 cm; 83.0 ±â€¯14.0 kg) were tested using the 30 s Wingate anaerobic test (WAnT) during three separate testing sessions. RESULTS: There were no differences in [BL] between any of the conditions immediately or 5 min posttest. There were also no differences in peak, relative or average power, or fatigue index during the WAnT. The UAAB mouthguard was therefore unsuccessful in improving anaerobic performance. CONCLUSION: It is likely that more expensive, custom-fit dental mouthguards may be necessary for individuals to see any benefits to athletic performance.

Modality determines VO2max achieved in self-paced exercise tests: validation with the Bruce protocol.

PURPOSE: The Bruce protocol is traditionally used to assess maximal cardiorespiratory fitness (VO2max), but may have limitations, such as an unknown duration and large work rate increases. The use of self-paced VO2max tests (SPVs) may be beneficial if they are able to elicit similar maximal values in a set period of time. In addition, differences in modality between SPVs have not been explored. The purpose of this study was to compare SPVs, utilizing two different modes, with the Bruce (treadmill) protocol. METHOD: Thirteen healthy, recreationally active individuals (eight men, five women) volunteered and participated in three different laboratory visits with each utilizing a different VO2max testing protocol. The first visit consisted of the Bruce protocol test, and the remaining visits entailed a maximal SPV on a treadmill (TM SPV) and a cycle ergometer (CE SPV). RESULTS: There were no differences in VO2max values between the TM SPV and the Bruce protocol tests (55.6 ± 4.9 vs. 56.2 ± 6.8, respectively; p = .510). As expected, the CE SPV (48.3 ± 7.6) was significantly lower than the other two tests (p < .001). CONCLUSION: The TM SPV was as effective in eliciting an accurate VO2max as the Bruce protocol and did so with less incline and in less time suggesting that there are no changes in the limits of VO2max even when the test is self-paced and perceptually regulated.

The Effect of Rocktape on Rating of Perceived Exertion and Cycling Efficiency.

The purpose of this study was to investigate the effects of Rocktape (RT), a type of kinesiology tape, on perceived exertion and cycling efficiency. Eighteen recreational cyclists volunteered as subjects for this study. Four experimental conditions were used: (a) 60% VO2peak with RT, (b) 60% VO2peak without RT, (c) 80% VO2peak with RT, and (d) 80% VO2peak without RT. The Borg rating of perceived exertion (RPE) scale was used to evaluate subjective exertion during the cycling bouts. Overall RPE and leg, arm, and chest RPEs were obtained (RPE-O, RPE-L, RPE-A, and RPE-C, respectively). Gross cycling efficiency was determined by calculating the ratio of the amount of work performed to the energy expended. Repeated-measures analysis of variance was used to investigate the differences between the 2 intensities and 2 tape conditions. There were main effects of intensity (p < 0.001) and tape (p = 0.02) found for the RPE-O, with RPE-C showing similar results for intensity (p < 0.001) and tape (p = 0.02). Similar findings were present for the RPE-C, and main effects of intensity (p < 0.001) and tape (p = 0.02) were discovered. A significant main effect of intensity was found for efficiency (p = 0.03), with the 80% intensity condition showing a greater level of efficiency than the 60% intensity condition. However, the use of RT did not increase gross efficiency (p = 0.61). The main finding in this study was that subjects reported a lower level of exertion overall and at the chest, which may lead to increases in overall performance of these athletes. The use of RT before athletic events should not be discouraged.

Childhood obesity prevention: an intervention targeting primary caregivers of school children.

Community-based participatory research (CBPR) was used to design and evaluate the effectiveness of a culturally relevant, science-based intervention for the prevention of childhood obesity in the Commonwealth of the Northern Mariana Islands (CNMI), a US Commonwealth in the western Pacific. This cognitive behavioral lifestyle intervention, Project Familia Giya Marianas (PFGM), was offered during the 2005-2007 school years in all CNMI public elementary schools over eight sessions to primary caregivers of 3rd grade children (N = 407). A crossover design was utilized with half of the schools offering the intervention in the Fall term, while the other half delivered the sessions in the Spring term. The primary outcome measure was change in BMI z-score. There was an intervention-dependent effect on BMI z-score, with program impact being a function of baseline BMI and the number of lessons attended. This effect was most apparent in students whose baseline BMI z-score was in healthy range (>/=5 to <85 percentile). In both Asian and Pacific Island groups, children whose caregivers completed 5-8 lessons experienced a significant change in BMI z-score as compared to those with 0 lessons (P < 0.05). Research that integrates multidisciplinary and multimethod approaches is effective in identifying and/or devising solutions to address a complex condition such as childhood obesity. PFGM demonstrated that community participation can be successfully utilized in the development and implementation of childhood obesity prevention programs.

Comparisons of cubed ice, crushed ice, and wetted ice on intramuscular and surface temperature changes.

CONTEXT: Many researchers have investigated the effectiveness of different types of cold application, including cold whirlpools, ice packs, and chemical packs. However, few have investigated the effectiveness of different types of ice used in ice packs, even though ice is one of the most common forms of cold application. OBJECTIVE: To evaluate and compare the cooling effectiveness of ice packs made with cubed, crushed, and wetted ice on intramuscular and skin surface temperatures. DESIGN: Repeated-measures counterbalanced design. SETTING: Human performance research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twelve healthy participants (6 men, 6 women) with no history of musculoskeletal disease and no known preexisting inflammatory conditions or recent orthopaedic injuries to the lower extremities. INTERVENTION(S): Ice packs made with cubed, crushed, or wetted ice were applied to a standardized area on the posterior aspect of the right gastrocnemius for 20 minutes. Each participant was given separate ice pack treatments, with at least 4 days between treatment sessions. MAIN OUTCOME MEASURE(S): Cutaneous and intramuscular (2 cm plus one-half skinfold measurement) temperatures of the right gastrocnemius were measured every 30 seconds during a 20-minute baseline period, a 20-minute treatment period, and a 120-minute recovery period. RESULTS: Differences were observed among all treatments. Compared with the crushed-ice treatment, the cubed-ice and wetted-ice treatments produced lower surface and intramuscular temperatures. Wetted ice produced the greatest overall temperature change during treatment and recovery, and crushed ice produced the smallest change. CONCLUSIONS: As administered in our protocol, wetted ice was superior to cubed or crushed ice at reducing surface temperatures, whereas both cubed ice and wetted ice were superior to crushed ice at reducing intramuscular temperatures.

Subcutaneous tissue thickness alters the effect of NMES.

CONTEXT: No direct research has been conducted on the relationship between subcutaneous tissue thickness and neuromuscular electrical stimulation (NMES). OBJECTIVE: The purpose of this study was to determine the effects of subcutaneous tissue thickness on NMES amplitude and NMES force production of the quadriceps. DESIGN: Simple fixed design, testing the independent variable of subcutaneous thickness (skinfold) groups with the dependent variables of NMES amplitude and force production. SETTING: Athletic Training Laboratory. PARTICIPANTS: 29 healthy women. INTERVENTION: NMES to produce at least 30% of maximal voluntary isometric contractions (MVIC) of the quadriceps. MAIN OUTCOME MEASURE: Maximal NMES amplitude and percentage of MVIC using NMES. RESULTS: A significant skinfold category difference F2,28=3.92, P=.032 on NMES amplitude was found. Post hoc revealed the thinnest skinfold category tolerated less amplitude compared to the thickest category. A significant correlation was found between NMES amplitude skinfold category R=.557, P=.002. CONCLUSION: Higher NMES amplitudes are needed for the thickest skinfold category compared to the thinnest skinfold category.

Intramuscular temperature differences between the mid-point and peripheral effective radiating area with ultrasound.

The purpose of the study was to determine whether uniform intramuscular heating is achieved throughout a treatment area 2 times the transducer head at both 1 and 3 MHz. Seven male and three female subjects (Age: 23.6 ± 1.0 yrs, Weight: 83.8 ± 23.2 kg, Site Skinfold: 13.9 ± 7.3 mm) underwent two ultrasound treatments (1 and 3 MHz) in the triceps surae muscle group. Thermocouples were inserted at the midpoint and periphery of the treatment area. Ten minute baseline temperatures were recorded followed by a ten minute ultrasound treatment. Two (site) X 10 (time) repeated measures ANOVAs were separately used to determine significance for 1 and 3 MHz treatments. Post-hoc testing was performed using the Bonferroni adjustment. A significant site-by-time interaction was observed for both the 1 and 3 MHz treatments. From baseline to the end of the treatment, temperature increased approximately 2.62°C and 1.58°C for the midpoint and periphery of the 1 MHz treatment and 5.88°C and 3.64°C for the 3 MHz treatment. The differences in temperature suggest that uniform heating does not occur throughout the treatment area. Key points3 MHz is more effective in raising intramuscular temperature within ERA.Stroke count/rate of transducer may play a factor in heating tissue.Treatment size may alter uniform heating.

The effects of bicycle frame geometry on muscle activation and power during a wingate anaerobic test.

The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes' to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Key PointsRoad cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing.Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon.Increasing the seat tube angle from 72 to 82 enabled triathletes' to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle.Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length.

The effects of a 6-week plyometric training program on agility.

The purpose of the study was to determine if six weeks of plyometric training can improve an athlete's agility. Subjects were divided into two groups, a plyometric training and a control group. The plyometric training group performed in a six week plyometric training program and the control group did not perform any plyometric training techniques. All subjects participated in two agility tests: T-test and Illinois Agility Test, and a force plate test for ground reaction times both pre and post testing. Univariate ANCOVAs were conducted to analyze the change scores (post - pre) in the independent variables by group (training or control) with pre scores as covariates. The Univariate ANCOVA revealed a significant group effect F2,26 = 25.42, p=0.0000 for the T-test agility measure. For the Illinois Agility test, a significant group effect F2,26 = 27.24, p = 0.000 was also found. The plyometric training group had quicker posttest times compared to the control group for the agility tests. A significant group effect F2,26 = 7.81, p = 0.002 was found for the Force Plate test. The plyometric training group reduced time on the ground on the posttest compared to the control group. The results of this study show that plyometric training can be an effective training technique to improve an athlete's agility. Key PointsPlyometric training can enhance agility of athletes.6 weeks of plyometric training is sufficient to see agility results.Ground reaction times are decreased with plyometric training.