Whole-body vibration (WBV) may positively influence performance acutely through the potentiation of the muscle’s series elastic components and neuromuscular mechanisms. The purpose of this investigation was to examine the acute effects of WBV on sprint performance in NCAA Division I collegiate male sprinters and jumpers. Twenty-one athletes (n=21) completed a control or WBV protocol (30 seconds, 50 Hz, low amplitude ~3mm) one minute before a 30 m flying sprint. Each athlete participated in three separate trials using randomized treatment sessions (1 treatment per session) over 12 weeks of preparation training prior to the indoor season. The control condition consisted of no vibration, while treatment 1 (T1) and treatment 1 repeated (T1-R) incorporated vibration. The vibration-sprint protocol was repeated after a five minute rest period following the first sprint (test-re-test ICC≥0.81). The sprint consisted of a 15 m run-in from a standing start and a 30 m flying sprint with a total distance of 45 m. A two-way factorial ANOVA with repeated measures (p ≤ 0.05) was used to compare treatments. Statistics showed no differences between the treatments at all distances (average sprint time of control vs. T1, control vs. T1-R, and T1 vs. T1-R). The results of this study indicate that WBV at 50 Hz and low amplitude has no potentiation effect on sprint times (15, 30, 45, or 30 m fly). Further research is needed to determine if different WBV protocols may elicit enhanced results in 30 m flying sprint performance. The present WBV protocol does not appear to have practical acute value for sprinting.

Various aspects of performance (e.g., sprint speed, grip strength) are thought to be important determinants of the success of animals in natural activities such as foraging, mating, and escaping from predators. However, it is generally known that morphological properties enhancing one type of performance (e.g., speed) can lead to a reduction in another (e.g., strength). Such performance trade-offs have been quantified at the inter-specific level, but evidence at the inter-individual level remains equivocal. To test for the presence of a performance trade-off, I initiated a study on wild white-footed mice (Peromyscus leucopus). In summer 2016, I captured a total of 186 individuals, 87 of which were repeatedly phenotyped for grip strength and sprint speed. A significant positive relationship was found between body mass and grip strength (but not for sprint speed). Individual differences in performance were repeatable through time for both grip strength and sprint speed. Using a bivariate mixed model, I detected a significant negative correlation between grip strength and sprint speed at the among-individual level. By contrast, the within-individual correlation between grip strength and sprint speed tended to be positive, suggesting that some unquantified aspects of the mouse phenotype (e.g., body condition, age) may have a positive effect on both performance traits. Given the relatively low repeatability of grip strength and sprint speed, a failure to properly partition the correlation at the among- and within-individual level generates a counter-intuitive, positive correlation. This study is one the first to detect a performance trade-off at the among-individual level in a wild animal population.

The purpose of this study was to identify a potentiation effect on 30 meter (m) fly sprint performance in collegiate sprinters and jumpers (M=21, W=5) following an acute bout of whole-body vibration. The WBV protocol consisted of one 30 second bout at 50 Hz, ~3 mm amplitude, and 60 seconds rest before a 30m fly sprint. Sprint times were measured using timing gates, and characteristics of strength and power were measured using a force plate. Analysis included measures of jump height, peak power, peak force, and rate of force development. Each subject participated in 3 separate trials using randomized treatment sessions over 3 months of preparation training. The control condition consisted of no vibration and WBV treatment 1 and 2 incorporated vibration. Statistics comparing the average sprint times showed no treatment effects. The results of this study indicate that WBV at 50 Hz and ~3 mm amplitude has no effect on sprint times.

One very common axiom amongst Strength and Conditioning Professionals and Athletic Performance Coaches is that the least flexible athletes usually produce the fastest 40-yard dash times. Flexibility, in this case specifically refers to posterior chain flexibility (PCF). This is usually measured by athletes ability to perform a sit-and-reach test. This train of thought has been widely accepted within the human performance professions, even though it is void of any scientific investigation or measured validity. The purpose of this study is to determine if there is a relationship between posterior chain flexibility using the sit-and-reach test and speed in the 40-yard dash. All test subjects were male between the ages of 18-22, and members of a Division I university football team. All 95 test subjects had participated in at least one semester of a strength and conditioning program designed by Certified Strength and Conditioning Specialists. Similar of the study done by Johnson (2001), each athlete was placed in a group based on position, line of scrimmage groups (LOS), Skill group (receivers, cornerbacks, rover linebackers, whip linebackers, and safeties), Combo group (inside linebackers, tight ends, quarterbacks, tailbacks, fullbacks, and defensive ends), Specialist group (place- kickers, kick-off specialists, holders, and punters). Each test subject was tested in the 40-yard dash, the sit-and-reach flexibility test, as well as other tests for strength and power such as the bench press, front squat, push jerk, power clean, vertical jump, and agility tests. Body weight and height was also measured. This study used a simple linear regression on the data where the Sit-and-Reach test results were the dependent variable and the subjects timed results in a 40 yard dash was the independent variable. There appears to be no significant relationship between a low flexibility score and the sprint speed of an athlete for the entire group population. The results also show that there is no significant relationship between flexibility of the posterior chain and linear speed as measured in the 40-yard dash when looking at football players that fall under the Combo, Skill, or LOS position groups. There was however a significant relationship for the specialist group. The theory that the least flexible athletes usually produce the fastest 40-yard dash times is not true for those specific groups. / Ph. D.

Bakgrund: Innebandy är en intensiv sport där snabba upprepade accelerationer och riktningsförändringar är viktiga ingredienser för framgång. Även om både förflyttningssnabbhet och uthållighet är viktiga för prestationen i innebandy, finns inga studier som undersöker hur de relaterar till varandra och andra viktiga fysiska kvaliteter. Syfte: Att beskriva kvinnliga elitinnebandyspelares fysiska egenskaper och undersöka korrelationen mellan snabbhet i förflyttningar, aerob uthållighet, maximal styrka och explosivitet. Metod:19 kvinnliga elitinnebandyspelare i åldern (medel (SD)) 21,8år (±2,15), längd 168,8cm (±5,8) långa och vikt 65,9 kg (±6,3), rekryterades till studien. Ett testbatteri genomfördes över två dagar och bestod av snabbhetstester (Acc10, Acc20m, Pro-agility), explosivstyrketester (SLH, SJ, CMJ, CMJ:A), maximalstyrketest (IPU) och aerob uthållighet (Beeptest). Korrelationen mellan testresultaten analyserades. Resultat: Det fanns starka korrelationer mellan förflyttningssnabbhet och prestationen explosiv styrka, utom mellan vertikalhopp med armsving (CMJ:A) och snabbhet i riktningsförändringar (Pro- agility). Isometrisk styrka (IPU) relaterade endast signifikant till snabbhet i riktningsförändringar (Pro-agility), vilket också aerob uthållighet (Beeptest) gjorde. Slutsats: För kvinnliga elitinnebandyspelare finns ett samband mellan explosiv styrka och snabbhet i alla förflyttningar, medan maximalstyrka endast verkar relatera till snabbhet i riktningsförändringar. Arbetsförmågan i aerob uthållighetsarbeten verkar inte påverka prestationen i snabbhet negativt, utan på den här prestationsnivån kan båda utvecklas till tillräcklig nivå. / Background: Floorball is an intense sport where rapid repeated accelerations and changes of direction are important ingredients for success. Although both the locomotion speed and endurance are essential for achievement in floorball, there are no studies examining how they relate to each other and other important physical qualities. Objective: To describe female elite Floorball player's physical properties and examine the correlation between locomotion speed, aerobic endurance, maximum strength and explosiveness. Method: 19 female elite Floorball players age (mean (±SD)) 21, 8 years (±2.15), height 168, 8 cm (±5.8) and weight (65.9 kg±6.3), were recruited to the study. A test battery was conducted over the span of two days and consisted of tests of locomotion speed (Acc10, Acc20, Pro-agility), explosive strength (SLH, SJ, CMJ, CMJ:A), maximum strength (IPU) and aerobic endurance (Beep test). The correlation between the test results were analyzed. Results: There were strong correlations between locomotion speed performance and explosive strength, except between vertical jump with arm swing (CMJ) and speed in changes of direction (the Pro agility). Isometric strength (IPU) significantly related to the speed in changes of direction (the Pro agility), as did aerobic endurance (Beeptest). Conclusion: For female elite Floorball players there seems to be a correlation between explosive strength and quickness in all types of locomotion, while the maximum strength only seems to relate to the speed in changes of directions. Work ability in aerobic endurance tasks does not seem to affect performance in locomotion speed, and at this performance level both can be developed to a sufficient level.

The purpose of this dissertation was to explore the interrelationships of several important fitness characteristics in Division 1 athletes. Sport performance magnitude is the summation of an individual athlete’s technical, psychological, and fitness characteristics. Athletes who excel in any or all characteristics perform better in their chosen sports. General fitness characteristics that are important to almost all sports include strength, power, vertical jump height, shortdistance sprinting ability, muscularity, and body fat percentage. These variables have been shown in previous research to independently affect athletic performance outcomes, but their relationships to one another are less clear. Eighty Division I athletes from 4 sports were examined in a variety of fitness characteristics as part of a continuous athlete monitoring program. Data on strength, power, vertical jump height, short-distance sprinting speed, muscularity, and body fat percentage were collected and analyzed. Analysis revealed several important relationships. Firstly, strength is highly related to muscularity, with lean body mass as one of the most important determinants of strength. Secondly, athletes who can produce high relative (scaled per body mass) forces and powers tend to be considerably higher jumpers and much faster sprinters. Lastly, leaner athletes out-perform less lean athletes in almost every metric, especially relative strength and power, vertical jumping ability, and sprinting ability.