Jeni R. McNeal

Comparison of the Wingate and Bosco anaerobic tests.

The purpose of this study was to compare the Wingate cycling and Bosco repeated jumps anaerobic tests. Eleven men (21.36 ± 1.6 years; 179.1 ± 9.3 cm; 78.7 ± 11.0 kg) and 9 women (21.89 ± 3.66 years; 171.8 ± 10.0 cm; 75.9 ± 21.4 kg), all university athletes, volunteered to participate. Subjects performed each test in random order. The tests consisted of a 30-second Wingate test and a 60-second Bosco test. The Wingate test was conducted using a Monark cycle ergometer and the Bosco test was conducted on a force platform. Following the performance of each test, peak lactate concentrations were determined. Average and peak power values were statistically greater in men and on the Bosco test. Peak lactate values were statistically greater in men but did not differ based on test. Correlations between peak lactate concentrations between tests and lactate values with peak or average power were not statistically significant. The relationship between peak power between tests was statistically significant among men, but not women. The results of the study indicated that the Bosco and Wingate tests, which both measure anaerobic characteristics, appear to measure different aspects of anaerobic power and capacity. The Bosco test also may be inappropriate for athletes who are not well trained in jumping.

Skeleton: Anthropometric and physical abilities profiles: US national skeleton team

Abstract The aim of this study was to characterize sprint ability, anthropometry, and lower extremity power in the US National Team Skeleton athletes. Fourteen athletes (male n = 7; mean ± SD: height 1.794 ± 0.063 m, body mass 81.2 ± 3.7 kg, age 26.9 ± 4.1 years; female n = 7; 1.642 ± 0.055 m, 60.1 ± 5.9 kg, 27.3 ± 6.9 years) volunteered to participate. Sprinting ability was measured over multiple intervals using custom infrared timing gates in both an upright and a crouched sprint. The crouched sprint was performed while pushing a wheeled‐simulated skeleton sled on rails on an outdoor skeleton and bobsleigh start track. Crouched skeleton sprint starts were able to achieve about 70% to 85% of the upright sprint times. The mean somatotype ratings for females were: 3.5‐3.5‐2.1, and males: 3.6‐4.9‐1.9. Lower extremity strength and power were measured via vertical jumps on a portable force platform using squat and countermovement jumps, and jumps with added mass. Jump height, power, rate of force development and peak force were determined from force‐time data. Lower extremity strength and power were strongly correlated with both upright and crouched sprint times. The results indicated that these athletes are strong sprinters with varying body structures, mostly mesomorphic, and that stronger and more powerful athletes tend to be better starters.The aim of this study was to characterize sprint ability, anthropometry, and lower extremity power in the US National Team Skeleton athletes. Fourteen athletes (male n = 7; mean +/- SD: height 1.794 +/- 0.063 m, body mass 81.2 +/- 3.7 kg, age 26.9 +/- 4.1 years; female n = 7; 1.642 +/- 0.055 m, 60.1 +/- 5.9 kg, 27.3 +/- 6.9 years) volunteered to participate. Sprinting ability was measured over multiple intervals using custom infrared timing gates in both an upright and a crouched sprint. The crouched sprint was performed while pushing a wheeled-simulated skeleton sled on rails on an outdoor skeleton and bobsleigh start track. Crouched skeleton sprint starts were able to achieve about 70% to 85% of the upright sprint times. The mean somatotype ratings for females were: 3.5-3.5-2.1, and males: 3.6-4.9-1.9. Lower extremity strength and power were measured via vertical jumps on a portable force platform using squat and countermovement jumps, and jumps with added mass. Jump height, power, rate offorce development and peak force were determined from force-time data. Lower extremity strength and power were strongly correlated with both upright and crouched sprint times. The results indicated that these athletes are strong sprinters with varying body structures, mostly mesomorphic, and that stronger and more powerful athletes tend to be better starters.

Stretching for performance enhancement.

Stretching exercises have been considered an essential component of physical training programs for decades. Cross-sectional studies have demonstrated that flexibility measures are related to performance in many sports, suggesting that using stretching to enhance flexibility may indirectly improve performance. However, observations by athletes and coaches have called into question the universal prescription of stretching for the purpose of enhancing sport performance, and this skepticism is being supported by a growing body of empirical data. Whereas the tissue responses and adaptations to stretching have been the most widely studied area of stretching research, comparatively little is understood regarding the neural influences on range of motion, which may have more applicability when the range of motion needs are related to skilled movements as in sport.

The effect of vibration on active and passive range of motion in elite female synchronized swimmers.

Abstract The purpose of this study was to assess the acute effects of vibration and stretching on passive and active forward split range of motion in elite adult female synchronized swimmers. Eleven athletes performed a passive forward split test measuring the height of the anterior superior iliac spine on both sides and an active split test on both sides by adopting an inverted split position. Then athletes were assigned randomly by right or left leg to receive vibration on one leg while stretching. The contralateral leg was stretched but did not receive vibration and served as the control. The treatment involved a 40-s exposure to vibration of the forward leg in a split and 40 s of vibration to the rear leg in a split. The athletes were then post-tested using the same protocols. The results indicated that the vibration had a statistically significant influence on passive forward split flexibility, but not active split flexibility. The results of this study confirm earlier work and further demonstrate the efficacy of vibration in enhancing range of motion in a passive split position. Given that it is often difficult to achieve large changes in range of motion with already highly trained elite athletes, this methodology shows considerable promise. Vibration may not be powerful enough to evoke changes in active range of motion in spite of the changes in passive range of motion.

Dynamic Compression Enhances Pressure-to-pain Threshold in Elite Athlete Recovery: Exploratory Study

Abstract Sands, WA, McNeal, JR, Murray, SR, and Stone, MH. Dynamic compression enhances pressure-to-pain threshold in elite athlete recovery: exploratory study. J Strength Cond Res 29(5): 1263–1272, 2015—Athlete recovery-adaptation is crucial to the progress and performance of highly trained athletes. The purpose of this study was to assess peristaltic pulse dynamic compression (PPDC) in reducing short-term pressure-to-pain threshold (PPT) among Olympic Training Center athletes after morning training. Muscular tenderness and stiffness are common symptoms of fatigue and exercise-induced muscle microtrauma and edema. Twenty-four highly trained athletes (men = 12 and women = 12) volunteered to participate in this study. The athletes were randomly assigned to experimental (n = 12) and control (n = 12) groups. Pressure-to-pain threshold measurements were conducted with a manual algometer on 3 lower extremity muscles. Experimental group athletes underwent PPDC on both legs through computer-controlled circumferential inflated leggings that used a peristaltic-like pressure pattern from feet to groin. Pressures in each cell were set to factory defaults. Treatment time was 15 minutes. The control group performed the same procedures except that the inflation pump to the leggings was off. The experimental timeline included a morning training session, followed by a PPT pretest, treatment application (PPDC or control), an immediate post-test (PPT), and a delayed post-test (PPT) after the afternoon practice session. Difference score results showed that the experimental groups PPT threshold improved after PPDC treatment immediately and persisted the remainder of the day after afternoon practice. The control group showed no statistical change. We conclude that PPDC is a promising means of accelerating and enhancing recovery after the normal aggressive training that occurs in Olympic and aspiring Olympic athletes.

Muscle activation characteristics of tumbling take-offs

In the floor exercise, a gymnast may receive a general composition score deduction associated with a lack of diverse tumbling sequences. Diversity in tumbling is defined as the ability to tumble both forward and backward, as well as twist and flip. A coachs ability to direct technical and physical training for these skill varieties is enhanced when thorough descriptions of the skills are available. The aim of this study was to describe and compare muscle activation of the lower extremity in various tumbling sequences characterized by differing body orientations. The stretch–shortening cycle actions during the take-off portion of four different tumbling sequences were analysed and the results compared across muscles and type of take-off (forward vs. backward, twisting vs. non-twisting). Thirteen female gymnasts performed three trials each of round-off flic-flac to backward layout and to backward layout with longitudinal axis twist, and front flic-flac to forward layout and to forward layout with longitudinal axis twist. Activation onset was assessed as an increase of the EMG of 200% above noise before initial floor contact. The EMG was normalized to peak values for each muscle bilaterally during each take-off. Results showed that muscle activation characteristics in the pre-activation and impact phase (contact to maximal floor depression) differed between tumbling series. Backward take-offs were characterized by longer contact times, greater relative activity of the gastrocnemius compared with the vastus lateralis during pre-activation, and greater biceps femoris activation during impact compared with forward take-offs. Twisting backward was associated with reduced muscle activity of the twisting limb, while twisting forward was associated with increased muscle activation on the twisting limb. These differential effects related to the specific nature of the take-off indicate that training to enhance the stretch–shortening cycle action in gymnasts must be specific to the orientation requirements of each specific skill.

Plaudits and pitfalls in studying elite athletes

The study of elite athletes, because of their rarity, renders statistical power difficult to achieve, control groups difficult or impossible to find, and generalizability difficult to demonstrate. Alternative methods of analysis may be better suited to such study.

Peristaltic pulse dynamic compression of the lower extremity enhances flexibility.

Abstract Sands, WA, Murray, MB, Murray, SR, McNeal, JR, Mizuguchi, S, Sato, K, and Stone, MH. Peristaltic pulse dynamic compression of the lower extremity enhances flexibility. J Strength Cond Res 28(4): 1058–1064, 2014—This study investigated the effects of peristaltic pulse dynamic compression (PPDC) on range-of-motion (ROM) changes in forward splits. Serious stretching usually involves discomfort and large time investments. Tissue structural changes and stretch tolerance have heretofore been considered the primary mechanisms of enhanced ROM. The PPDC treatment was computer controlled. Circumferential and segmented inflation pressures were induced by feet to hip leggings. Nine subjects, experienced in stretching and a forward split position, volunteered. The subjects were familiarized with the protocol and randomly assigned to an initial condition: experimental (PPDC), or control (CONT). The study involved a crossover design. Second conditions were tested within 1–5 days. All tests were 2 trials of right and left forward splits. Split flexibility was assessed by measuring the height of the anterior superior iliac spine of the rear leg from the floor. Pelvic posture was controlled by rear leg position. The PPDC treatment was 15 minutes of seated PPDC. The control condition was the same except that leggings were not inflated. Pressures of 5 cells in the leggings were set at factory defaults, 70 mm Hg sequentially. Difference score results indicated statistically significant (p ⩽ 0.05) differences by condition and the condition by leg interaction. The rapid acute changes in ROM (PPDC: right 25.3%, left 33.3%; CONT: right 12.2%, left 1.0%) support the premise that changes in ROM were dependent on mechanisms other than tissue structural changes and/or stretch tolerance. PPDC provides a means of rapidly enhancing acute ROM requiring less discomfort and time.

Comparison of Commercially Available Disposable Chemical Hand and Foot Warmers

Abstract Objective.—Small chemical hand and foot warmers are used by many winter sport athletes and other outdoor enthusiasts. The purpose of this study was to characterize the thermal behaviors of 14 commercially available hand and foot warmers. Methods.—Both types of warmers were instrumented with a fast-responding thermistor. One of each pair of warmers was placed in a boot or glove. Temperature was recorded in a data logger for a period of hours to more than a day until the heat output of the devices ceased and returned to room temperature. Thermal behaviors were characterized and graphed, including peak temperature, time to peak temperature, and duration of temperature greater than 30°C. Reliability was determined by comparing thermal behavior of 2 hand or foot warmers of the same type and from the same manufacturer. Comparisons were also made between package claims and measured behaviors. Results.—Measured outcomes were most noteworthy in their variability within and between manufacturers and types of warmers. A strong correlation was found between the masses of the warmers and their duration of heat production. Conclusions.—Although there is a paucity of research information on these types of warmers, this experiment showed that some of the devices exceeded packaging claims while others fell short; that the thermal behavior over time of the devices was variable; and that there appears to be a simple but strong relationship between the mass of the devices and the duration of their heat production.

Acute effects of vibration-assisted stretching are more evident in the non-dominant limb

Abstract The aim of this study was to investigate the acute effects of a vibration-assisted static stretching intervention on enhancing split range of motion in gymnasts matched on initial range of motion. Twenty-two female artistic gymnasts (mean age 13.8 years, s=2.3) matched for age (±6 months) and competitive level were randomly assigned to a static stretching intervention with or without simultaneous vibration. The test consisted of adopting a forward split position with the rear leg bent to 90° and held vertically against a matted block while the pelvis remained perpendicular to the lines of the two legs. The gymnast was instructed to descend into the lowest split position of her comfortable pain tolerance. Positions were videotaped and digitized creating an angle between the split legs. The stretching intervention consisted of a forward split position with emphasis on the front leg hamstring muscle group, followed by a forward lunge position with emphasis on the rear leg quadriceps muscle group. In each position, four sets of stretches were completed each of 10 s duration with 5 s of rest between sets. The experimental group performed stretches with the vibration device turned on while the control group performed the same stretches with the vibration device turned off. A pre-test was performed to obtain baseline scores with the post-test following immediately after the vibration or control stretching intervention. Difference scores were calculated between the pre-test and post-test for each gymnast, and compared between groups using independent t-tests. Results showed significant post-test differences between the vibration and non-vibration groups (mean difference 12.2±5.2° vibration vs. 7.8±3.5° non-vibration, P=0.030) in the non-dominant limb, but no significant differences in the dominant limb (mean difference 10.2±4.3° vibration vs. 7.9±6.1° non-vibration, P=0.32). Vibration-assisted static stretching may provide a greater stimulus for range of motion improvements in limbs that have a lower initial level of flexibility.