Effects of Medicine Wall Ball Throws With Whole-Body Vibration on Bat Swing Performance in Collegiate Baseball Players.

ABSTRACT: Buso, D, Willardson, JM, and Shafer, AB. Research note: Effects of medicine wall ball throws with whole-body vibration on bat swing performance in collegiate baseball players. J Strength Cond Res 37(10): 2071-2075, 2023-The purpose of this study was to examine the effect of medicine ball wall throws performed with whole-body vibration on bat swing performance in 13 highly trained collegiate baseball players. The experimental session involved the athletes' usual warm-up followed by baseline bat swings. The baseline bat swings were followed by 3 sets of 5 medicine ball wall throws while standing on a whole-body vibration platform set at 40 Hz and with 30 seconds rest between sets. Subjects then rested passively for 5 minutes before taking post-test bat swings. Performance was evaluated with bat speed (m·second-1), time to contact (secs), rotational acceleration (G's), and exit velocity (m·second-1). Paired t tests were used to compare baseline and post-test values (p ≤ 0.05). Effect size (d) statistics were also calculated to determine the magnitude of treatment effects. It was found that bat speed (p = 0.02; d = 0.22) and exit velocity (p = 0.03; d = 0.48) were significantly faster versus baseline, whereas rotational acceleration (p = 0.10; d = 0.23) and time to contact (p = 0.44; d = -0.12) were not significantly different from baseline, respectively. These results suggest that the addition of medicine ball wall throws with whole-body vibration can significantly increase key parameters of bat swing performance. Practitioners and coaches may consider including these combined exercise stimuli as part of workouts or during games for potentially greater success at the plate.

Validity and Reliability of the Polar A300's Fitness Test Feature to Predict VO2max.

The Polar A300 fitness watch includes a feature termed the 5-minute fitness test. This feature claims to estimate maximal oxygen consumption (VO2max) in healthy adults. The purpose of this study was to assess the validity and reliability of the Polar A300 "Fitness Test" VO2max estimation feature. Nineteen recreationally active young adult males (n=9) and females (n=10) completed a Bruce protocol treadmill protocol to assess VO2max, followed by two separate 5-minute Polar Fitness Test (VO2max estimation) trials. A Pearson's r test was used to determine the relationship between VO2max from the Bruce Test to each Polar watch VO2max estimate, as well as to a non-exercise VO2max prediction equation. Additionally, a One Way ANOVA assessed differences in absolute group means of the Polar results to the Bruce Test, and non-exercise prediction model. There was a statistically significant, moderate-strong relationship between the Polar and the criterion Bruce VO2max estimations with the first Polar Test (n=19; r=.635; p<.05), as well as the second (n=19; r=.645; p<.05). The average VO2max of the two Polar tests and the Bruce test show greatest positive correlation (n=19; r=0.655; p<0.001). The reliability of the Polar watch indicated significance between the test-retest results (n=19; r=.907; p<.05). Lastly, the positive correlation between the non-exercise predicted model and the Bruce Test was weaker than the polar predictions (n=19; r=.522; p<.05). Preliminary results conclude that the Polar A300 Fitness watch is a valid tool for estimation of VO2max.

Energy expenditure, cardiorespiratory, and perceptual responses to shallow-water aquatic exercise in young adult women.

INTRODUCTION: Aquatic exercise (AE) is a popular form of physical activity, yet few studies have assessed the individual's energy expenditure (EE) associated with a continuous bout of AE. Studies using indirect calorimetry to measure EE have reported limitations associated with test methodology and the ability to control individual's exercise intensity or tempo. PURPOSE: To evaluate EE and cardiorespiratory (CR) responses during a 40-minute shallow-water AE session in young adult women. METHODS: Twenty-one healthy women (aged 21.7 ± 3.4 years) completed an orientation practice session and a 40-minute shallow-water AE session using a traditional exercise class format and the SWEAT video-based instructional cuing program. The high-intensity interval format included the following segments: 1) warm-up (3 minutes); 2) CR segment ( 22 minutes); 3) muscular endurance segment (ME; 10 minutes); and 4) cool-down (5 minutes). Subject oxygen consumption (VO2; mL/kg/min), heart rate (HR) and OMNI overall ratings of perceived exertion (RPE-O) were assessed each minute. Average kcal/min1, metabolic equivalents (METs; 1 MET = 3.5 mL/kg/min), and total kcals per segment and for the overall session were calculated. RESULTS: The total subject EE throughout the 40-minute trial (including warm-up and cool-down segments) was 264 kcals, with an overall average of 6.3 kcals/min (5.6 METs).The average kcals/min expended throughout CR segments 2 through 6 was 8.05 (7.1 METs), with the Hoverjog segment producing the greatest average kcals/min at 8.3 (7.3 METs). The CR portion (22 min) contributed 65% of the total EE (171 kcals) of the 40-minute AE trial. For the overall AE trial, the highest and average subject VO2 achieved were 33.3 and 19.7 mL/kg/min, respectively. The average highest subject heart rate achieved was 177 beats per minute (bpm), equivalent to 90% of the participant's age-predicted HRmax. CONCLUSION: Energy expenditure during a 40-minute AE session met national recommendations for a daily moderate-to-vigorous bout of physical activity offering a viable alternative to land-based exercise. Because AE serves as a partial-weight bearing modality, future studies are needed to clarify the EE of shallow-water AE in apparently healthy and clinical populations.

Just noticeable difference in perception of physical exertion during cycle exercise in young adult men and women.

The purpose of this investigation was to describe the just noticeable difference (JND) in perceived exertion during cycle exercise. Males (n = 20) and females (n = 26) (21.4 ± 3.1 year) performed load-incremented cycle exercise to peak intensity. At the end of each minute, subjects rated their overall-body perceived exertion using the OMNI (0-10) rating of perceived exertion (RPE) scale. Individual regression derived the power output (PO) corresponding to RPE 5. This PO served as the standard stimulus (SS). On a separate occasion, four 5-min cycling bouts were performed with 5 min rest between bouts. During bouts 1 and 3 subjects cycled at the SS. During bouts 2 and 4 subjects adjusted the resistance to achieve a level of exertion just noticeably above/below the SS. The difference in final 30-s oxygen consumption (VO2) and PO between each JND bout and the previous SS were the above (JND-A) and below (JND-B) perceived exertion JNDs. JND-A and JND-B were compared between genders and between subjects exhibiting lower versus higher ventilatory threshold (VT) and VO(2PEAK) within genders for VO2 (l · min(-1), %VO(2PEAK)) and PO (W, %SS). JND-B was significantly (P < 0.05) greater than JND-A for VO2 and PO, when expressed in absolute (l · min(-1), W) and relative units (%VO(2PEAK), %SS). Males exhibited greater JND values than females in absolute, but not relative, units. Subjects with lower and higher VT and VO(2)PEAK exhibited similar JND values. The JND can serve as an effective tool to measure perceptual acuity and to determine individual ability to self-regulate prescribed exercise intensities.