Ashley A. Kavanaugh

Changes in Muscle Architecture, Explosive Ability, and Track and Field Throwing Performance Throughout a Competitive Season and After a Taper

Abstract Bazyler, CD, Mizuguchi, S, Harrison, AP, Sato, K, Kavanaugh, AA, DeWeese, BH, and Stone, MH. Changes in muscle architecture, explosive ability, and track and field throwing performance throughout a competitive season and after a taper. J Strength Cond Res 31(10): 2785–2793, 2017—The purpose of this study was to examine the effects of an overreach and taper on measures of muscle architecture, jumping, and throwing performance in Division I collegiate throwers preparing for conference championships. Six collegiate track and field throwers (3 hammer, 2 discus, 1 javelin) trained for 12 weeks using a block-periodization model culminating with a 1-week overreach followed by a 3-week taper (ORT). Session rating of perceived exertion training load (RPETL) and strength training volume-load times bar displacement (VLd) were recorded weekly. Athletes were tested pre-ORT and post-ORT on measures of vastus lateralis architecture, unloaded and loaded squat and countermovement jump performance, underhand and overhead throwing performance, and competition throwing performance. There was a statistical reduction in weight training VLd/session (d = 1.21, p ⩽ 0.05) and RPETL/session (d = 0.9, p ⩽ 0.05) between the in-season and ORT training phases. Five of 6 athletes improved overhead throw and competition throwing performance after the ORT (d = 0.50, p ⩽ 0.05). Vastus lateralis muscle thickness statistically increased after the in-season training phase (d = 0.28, p ⩽ 0.05) but did not change after the ORT. Unloaded countermovement jump peak force and relative peak power improved significantly after the ORT (d = 0.59, p ⩽ 0.05, d = 0.31, p ⩽ 0.05, respectively). These findings demonstrate that an overreaching week followed by a 3-week taper is an effective means of improving explosive ability and throwing performance in collegiate track and field throwers despite the absence of detectable changes in muscle architecture.

Effects of Short-Term Free-Weight and Semiblock Periodization Resistance Training on Metabolic Syndrome.

Abstract South, MA, Layne, AS, Stuart, CA, Triplett, NT, Ramsey, MW, Howell, ME, Sands, WA, Mizuguchi, S, Hornsby, WG, Kavanaugh, AA, and Stone, MH. Effects of short-term free-weight and semiblock periodization resistance training on metabolic syndrome. J Strength Cond Res 30(10): 2682–2696, 2016—The effects of short-term resistance training on performance and health variables associated with prolonged sedentary lifestyle and metabolic syndrome (MS) were investigated. Resistance training may alter a number of health-related, physiological, and performance variables. As a result, resistance training can be used as a valuable tool in ameliorating the effects of a sedentary lifestyle including those associated with MS. Nineteen previously sedentary subjects (10 with MS and 9 with nonmetabolic syndrome [NMS]) underwent 8 weeks of supervised resistance training. Maximum strength was measured using an isometric midthigh pull and resulting force-time curve. Vertical jump height (JH) and power were measured using a force plate. The muscle cross-sectional area (CSA) and type were examined using muscle biopsy and standard analysis techniques. Aerobic power was measured on a cycle ergometer using a ParvoMedics 2400 Metabolic system. Endurance was measured as time to exhaustion on a cycle ergometer. After training, maximum isometric strength, JH, jump power, and V[Combining Dot Above]O2peak increased by approximately 10% (or more) in both the metabolic and NMS groups (both male and female subjects). Over 8 weeks of training, body mass did not change statistically, but percent body fat decreased in subjects with the MS and in women, and lean body mass increased in all groups (p ⩽ 0.05). Few alterations were noted in the fiber type. Men had larger CSAs compared those of with women, and there was a fiber-specific trend toward hypertrophy over time. In summary, 8 weeks of semiblock free-weight resistance training improved several performance variables and some cardiovascular factors associated with MS.

Acute whole-body vibration does not affect static jump performance

Abstract Currently, whole-body vibration is being used to promote enhanced performance. Many coaches and athletes believe that it can acutely enhance explosive performance and power output. However, the scientific literature is unclear as to whether this enhancement occurs. The purpose of this study was to examine the acute effects of whole-body vibration on static jump performance, including jump height, peak force, rate of force development, and peak power. Fourteen recreationally active individuals (5 females, 9 males) participated in three separate randomized treatment sessions. Treatment 1 consisted of no vibration while treatment 2 and treatment 3 incorporated whole-body vibration. The whole-body vibration protocol consisted of three 30-s bouts of vibration performed at 30 Hz and low amplitude (~3 mm) with a 30-s rest between bouts. Treatment 1 was identical in duration to both treatments 2 and 3, but did not contain any vibration. Five minutes after each treatment, the participants performed the static jump protocols. Two (data averaged) non-weighted static jumps and two 20 kg weighted jumps were performed. Treatments 1 vs. 2, 1 vs. 3, and 2 vs. 3 were calculated for each variable at both 0 kg and 20 kg. Jump height, peak force, rate of force development, and peak power were analysed using a one-way analysis of variance with repeated measures. The intra-class correlations comparing the two trials of each jump for each of the three treatments were ≥0.92. Compared with the no-vibration condition, jump height showed a non-significant increase as a result of whole-body vibration for both unweighted and weighted jumps; peak force, rate of force development, and peak power were not statistically different. The results indicate that whole-body vibration has no effect on jump height, peak force, rate of force development or peak power during static jumping.

Injuries in Collegiate Women’s Volleyball: A Four-Year Retrospective Analysis

A four-year retrospective analysis of injury data was conducted on a collegiate (NCAA Division I) women’s volleyball team. Twenty athletes (Year 1: age = 19.4 ± 0.9 y, height = 175.2 ± 5.1 cm, body mass = 70.5 ± 10.2 kg; Year 2: age = 20.1 ± 1.0 y, height = 175.7 ± 4.7 cm, body mass = 69.5 ± 10.1 kg; Year 3: age = 20.1 ± 1.4 y, height = 173.8 ± 6.3 cm, body mass = 69.9 ± 10.8 kg; Year 4: age = 19.5 ± 1.4 y, height = 174.4 ± 8.6 cm, body mass = 72.7 ± 10.8 kg) participated in this study, accounting for 1483 total training exposures. Injury was defined as any damage to a body part, incurred during volleyball or strength and conditioning-related activities, which interfered with training and/or competition. Injury rate was normalized to the number of athletes and exposure and expressed as injuries per 1000 exposures. A total of 133 injuries were recorded. The most common injury was to the knee (left = 7.5%, right = 12.0%). Injuries occurred most often in volleyball practice (75.2%), followed by competition (20.3%), and strength and conditioning-related activities (4.5%). Non-contact injuries (upper body = 26.3%, lower body = 53.4%) were more common than contact injuries (upper-body = 13.5%, lower-body = 6.8%). An examination of injury rates relative to the training year revealed patterns in injury occurrence. Specifically, spikes in injury rate were consistently observed during periods of increased training volume that were preceded by breaks in organized training, such as the early pre-season and off-season training periods.

Static jump test performance is related to back squat strength in athletes

We examined a static jump tests relationship with back squat strength in collegiate athletes. Forty-one (n = 41) young (aged 20.8 ± 2.4 years), healthy volunteers reported estimated back squat one-repetition maximums and completed a static jump protocol. The static jump protocol included five loading conditions, and jump height was estimated via flight time from portable contact mats. Loading conditions for males (n = 19) included 0 kg (polyvinylchloride pipe), 20.42 kg, 43.10 kg, 61.25 kg, and 83.94 kg whereas females (n = 22) used 0 kg, 12.70 kg, 20.42 kg, 29.49 kg, and 43.10 kg. Relationships between back squat one-repetition maximums, jump height, ratio (jump height/system mass) at each loading condition, mean jump height and ratio across loading conditions, change in jump height and ratio per condition (ΔJH, ΔRatio), and performance slope (slope of best fit line for system mass vs. jump height) were evaluated. Amongst all subjects, large (r > 0.70), statistically significant correlations were found between back squat one-repetition maximums and jump height for the two lightest loading conditions, mean jump height, and performance slope. However, relationships varied by sex with mean jump height demonstrating the greatest consistency in both males and females. Mean jump height may be the most practical variable from this static jump protocol for monitoring training adaptations, particularly in relatively homogenous female collegiate athlete populations.

The Effect of 4 Months Whole Body Vibration of on Bone Mineral Density of Division I Cross Country/Distance Runners

Physical loading associated with certain activities such as resistance training and running has been shown to have an osteogenic effect. However, endurance sports such as Cross Country (XC) with higher volumes of smaller, repetitive stresses may have a deleterious effect on bone mineral density (BMD) and content (BMC). Whole body vibration (WBV) has been shown to be an effective means of increasing bone mineral accumulation in certain populations, typically older females. PURPOSE: The purpose of this study was to investigate whether WBV was an effective means of increasing BMD and BMC in Division I XC/distance runners during their competitive indoor and outdoor track season. METHODS: Ten D-1XC/ distance runners (5 males, 4 females) were randomly assigned to either a control group or an experimental group. Athletes in the experimental group performed 3 sets of 30 second vibration treatments at 30 Hz and an amplitude of 5 – 7 mm five days a week prior to their afternoon training sessions for 4 months. Mondays, Wednesdays, and Fridays the experimental group stood on the vibration unit (130 knee angle) while Tuesdays and Thursdays they supported themselves in the pushup position with arms locked. DXA (dual energy x-ray absorptiometry) was used to measure BMC(g) and BMD(g/cm). Sites measured by DXA (Lunar Prodigy, GE Health Care Systems) included in the total body, both hips (total, femoral neck, trochanter, shaft and Ward’s triangle area), the lumbar vertebrae and both distal forearms (radius UD, Ulna UD, radius 33%, ulna 33%, total radius and total ulna). From the total body measurements the following sites were separately examined: left and right arm, left and right leg, the spine and the skull. Total training miles from 4 months prior to the start of the study through the completion of the study were collected and compared. Statistically, the pre and post test data were compared using a two-tailed t-test. RESULTS: There were no significant differences in BMD and BMC at all sites measured between the groups prior to the start of the vibration protocol. Reported running volume was not significantly different between groups in the 4 months prior to both the pre and post DXA measures (P = 0.67). Neither BMD nor BMC were significantly different in either the control or the vibration group between the pre and post DXA measurements in any of the sites measured. CONCLUSION: The results suggest that 4 months WBV does not have an effect on BMD or BMC. This may be due to the duration of the study, the frequency and or amplitude used, varying upper and lower body stress through the week, or nutritional factors not measured. PRACTICAL APPLICATION: These results suggest that whole body vibration utilizing Figure. 1. XXXX.