The purpose of this study was to determine the acute effects of stretching and local vibration on flexibility and explosive strength in competitive female gymnasts. Flexibility was measured in the forward-split position and jump characteristics were recorded using a force plate. Analysis included flight time (FT), jump height (JH), peak force (PF), instantaneous forces, and rates of force development (RFDs). Randomly assigned and counterbalanced groups were: simultaneous vibration-stretching (VS) (n=22), stretching-only (n=7), and vibration-only (n=8). VS showed statistically greater measures of flexibility in both the right and left leg, favored and non-favored legs pre- versus post-treatment. Vibration-only group resulted in statistically greater right forward-split flexibility and non-favored leg flexibility. There were no statistical differences in JH, FT, PF, instantaneous forces, or RFDs in the VS, stretching-only, and vibration-only groups' pre- versus post-treatment tests. The conclusion was simultaneous vibration-stretching greatly increased flexibility while not altering explosive strength.

Monitoring progress of athletes is an essential component of the training process. Collegiate distance running coaches often use field tests to assess progress because of a lack of time and resources to do laboratory testing. The purpose of this dissertation was to examine the relationships between physiological and strength variables measured in a laboratory and field testing measures in collegiate distance runners. Collegiate distance runners completed a series of tests in the Sport Science laboratory at East Tennessee State University to obtain physiological and strength parameters, such as V̇ O2max and vertical jump height. The athletes then completed one of two field tests (either a 3 km time trial or a 3 minute all out run test). There were strong correlations between the laboratory measures and the field test performances. These results indicate that strength is an important factor in run performance. Also, a 3 km time trial and a 3 minute all out run test are suitable for athlete monitoring.

Abstract available in the Medicine and Sciences in Sports and Exercise.

Abstract available in the Medicine and Sciences in Sports and Exercise.

The purposes of this study were to examine the effectiveness of an athlete monitoring program in managing athlete neuromuscular fatigue across a men's collegiate soccer season as measured by changes in squat jump (SJ) height and to compare possible changes with the session rating of perceived exertion (sRPE) training load (TL). Eighteen outfield Division I men's college soccer players performed SJ testing before each game of the fall season in addition to a baseline measurement at the start of preseason. The athletes provided sRPE values after all training sessions, weight-training, and games. Linear mixed modeling was used to compare changes in SJ height across the season with the baseline, and a correlation coefficient and single-lag cross-correlation coefficient were calculated between TL and changes in SJ height. No statistically significant decreases in SJ height occurred across the season, although a moderate practical decline occurred after the preseason (−1.6 cm, effect size = −0.70). The correlation between TL and changes in SJ height was statistically nonsignificant, whereas the cross-correlation was significant (r = 0.18, p = 0.48 and r = 0.55, p = 0.02, respectively). The athlete monitoring program was successful in managing the athletes' neuromuscular fatigue across the season as evidenced by the maintenance of SJ height and positive relationship between TL and changes in SJ height. Thus, SJ monitoring may serve as a useful fatigue monitoring tool for collegiate soccer athletes. Future study is needed, relating changes in vertical jump performance to other markers of athlete preparedness and performance.

Abstract available in the Medicine and Sciences in Sports and Exercise.

Osteoporosis is one of the most common diseases experienced in the older adult population. This condition is not only costly to manage and treat, particularly so when osteoporotic fractures occur, but also negatively impacts functional health and health-related quality of life for many individuals. This indicates the need for more to be done to prevent osteoporosis from developing initially. While bone mineral density (BMD) testing recommendations are in place for women aged 65 and older and men aged 70 and older to diagnose osteoporosis, there currently are no BMD testing recommendations for preventive or screening purposes in the general, healthy, adult population. One potential screening tool for bone strength is a peak vertical jump test. Peak vertical jump height can be used as a proxy for lower body muscle power, which has been identified as an influential factor in determining bone mass and geometry, both of which are critical aspects of bone strength. This study ascertained the relationship between muscle power and bone strength, as well as the capacity of a peak vertical jump test to identify young adults with below-average areal BMD (aBMD). A total of 303 young adults (18 to 22 years, n=136 males, n=167 females) participated in these cross-sectional analyses. DXA was used to assess aBMD for total hip and femoral neck, and DXA images were used to calculate femoral neck section modulus (FN Z) values. Peripheral quantitative computed tomography (pQCT) was used to assess indices of bone strength at the tibia. Cortical bone area (CoA) and density-weighted polar section modulus strength-strain index (SSIp) were assessed at the 38% midshaft site, and bone strength index (BSI) was assessed at the 4% midshaft site. Lower body muscle power was predicted using peak vertical jump height and the Sayers et al. (1999) equation. Data were analyzed using Pearson bivariate and partial correlations to examine associations among bone strength outcomes and muscle power. Logistic regression was used to examine the probability of below-average bone strength based on muscle power. Receiver Operating Characteristic (ROC) curve analysis was used to show the tradeoff between sensitivity and specificity and to display the accuracy of a peak vertical jump test as an assessment tool for aBMD. Logistic regression indicated the odds ratio of below-average height-adjusted femoral neck aBMD decreased 5.4% for females and 3.6% for males per 50 Watts of power. ROC curve analysis showed the best sensitivity-specificity trade-off for identifying individuals with and without below-average aBMD was 5,038 Watts in males (sensitivity = 73.7%; specificity = 62.4%; AUC = 0.709, 95%CI = 0.572 - 0.847) and 3,261 Watts in females (sensitivity = 71.4%; specificity = 58.9%; AUC = 0.708, 95%CI = 0.586 - 0.829). These cut off values correspond to a vertical jump height of 54.39 cm and 36.16 cm for males and females, respectively. Taken together, the results of these analyses suggest acceptable sensitivity and specificity and moderate discriminate ability for using a measure of muscle power, assessed with a peak vertical jump test, to identify young adults with below-average aBMD.

Introduktion: Den vertikala hoppförmågan är viktigt för prestationen inom många idrotter. Att använda sig utav komplexträning som benböj och vertikala upphopp har i tidigare forskning visats ge signifikant förbättrad kraftutveckling. Post-Activation Potentiation (PAP) är ett fysiologiskt fenomen som ökar muskelspänningen och kraftutvecklingen i de arbetande musklerna, vilket kan implementeras under komplexträning. Syftet med studien var att undersöka om idrottare inom basket, fotboll, handboll och volleyboll får en gynnsam ökning på Countermovement jump with arm swing (CMJa) om de genomför benböj med en belastning på 50% och 80% av deras estimerade eller faktiskt uppmätta 1 repetition maximum (RM) innan test av CMJa. Metod: 9 män och 2 kvinnor, ålder 20.6±3.3, 181.4±7.4 cm, vikt, 76.9±12.6 kg, deltog där samtliga deltagare var aktiva inom någon av idrotterna basket, fotboll och handboll. Testdeltagarna utförde två set tunga benböj följt av fem set CMJa på en infraröd sensor. Resultat: Resultatet visade ingen signifikant förbättring över tid i hopphöjd hos aktiva bollidrottare (p=0.98). Slutsats: Resultatet tyder på att användandet av PAP med tunga benböj inte leda till förbättrad prestation på hopphöjden vid genomförande av CMJa hos bollidrottare. Resultatet i den här studien stödjer inte tidigare forskningsresultat om att det finns en positiv skillnad på hopphöjd efter tunga benböj över tid. / Introduction: The vertical jump ability is essential for performance in many sports. The use of complex training has in previous research been shown to provide significantly improved power development. Post-Activation Potentiation (PAP) is a physical phenomenon that increases muscle tension and the force development of the working muscles which can be implemented in complex training. The purpose of this study was to investigate whether athletes in basketball, football, handball and volleyball will have a favorable increase in Countermovement jump with arm swing (CMJa) if they perform heavier squats with a load of 50% and 80% of their estimated or measured 1 repeat maximum (RM) before CMJa. Method: 9 men and 2 women, age 20.6±3.3 years, height 181.4±7.4 cm, 76.9±12.6 kg body mass participated in the study. All participants were active in one of the sports basket, football, handball or volleyball. The participants performed two set of squats followed by five set of two repetition CMJas with a five minutes rest in between. An infrared sensor MuscleLab was used to analyze the jump height. Results: The result showed no significant difference between heavy squats and jump height in CMJa over time (p=0.98). Conclusion: Squats with 50% and 80% of 1RM do not seem to improve jump height performance in CMJ on team sports players. The result in this study does not support the results in previous studies showing a positive effect of heavy squats on maximal jump height.

BAKGRUND: Ishockey är en stor idrott med över 80000 aktiva spelare i Sverige. SYFTE: Syftet med denna studie var att fastställa huruvida det finns korrelation mellan tester rekommenderade av Svenska Ishockeyförbundet och prestationsförmåga på is. Vidare skulle testresultaten ställas i relation till antropometriska värden. METOD: Studiepopulationen rekryterades från hockeylag i division I. Testerna 1RM knäböj, stående längdhopp samt sergants jump utfördes enligt Svenska Ishockeyförbundets rekommenderade förfarande. Prestationsförmåga på is mättes genom 17 m sprintlopp. Korrelationen mellan testerna och prestation på is beräknades med pearsons korrelationskoeffecient. P<0.05 betraktades som signifikant. RESULTAT: Totalt rekryterades 34 ishockeyspelare från division 1 (100 % män, medel ± SD: ålder 22,7 ±2.24 år; vikt 85,3 ±6,4 kg; längd 182 ±6 cm). Av utförda tester var det endast 1RM knäböj/kroppsvikt-ratiot som med statistisk signifikans visades korrelera med prestationsförmågan på is (r=0,389, p=0,049). Övriga tester uppvisade ingen statistisk signifikans. SLUTSATS: Studiens resultat pekar mot att det finns en svag statistiskt signifikant korrelation mellan 1RM knäböj/kroppsvikt-ratio och sprintförmåga på is. Knäböj/kroppsvikt-ratiot svarar dock endast för en liten del av prestationsförmågan på is, varvid knäböjens starka position som grundövning utanför isen bör ifrågasättas. / BACKGROUND: Ice hockey is a large sport with over 80000 active players in Sweden. PURPOSE: The aim of this study was to determine whether there are correlations between tests recommended by the Swedish Ice Hockey Federation and on-ice performance. The results were also to be examined in relation to antropometric values. METHOD: The studypopulation was recruited from Swedish tier-III teams. The 1RM squat, standing long jump sand sergants jump were performed as described by the Swedish Ice Hockey Federations guidelines. On-ice performance was measured by a 17m sprint. The correlation between off- and on-ice tests were calculated using pearsons correlation coefficient. Statistical significance was set to P<0.05. RESULTS: Thirtyfour male ice hockey players from Swedish tier-III were recruited for the study (100% men, mean ± SD: age 22,7 ±2.24 years; weight 85,3 ±6,4 kg; length 182 ±6 cm). Out of the performed tests only 1RM squat/bodywight-ratio showed a statistical significant correlation to on-ice performance (r=0,389, p=0,049). The other tests did not show statistical significance. CONCLUSION: The results points towards a weak statistical significant correlation between 1RM squat/bodywight-ratio and on-ice sprinting ability. The 1RM squat/bodyweight-ratio however explained a small portion of on-ice performance, hence the squats strong position as basic exercise off-ice should be questioned.

The amylased object were healthy basketball players (22 - 26) and triathlonists (19 - 20) making jumps in different ways: CMJ - vertical jump with shockproof sit up (per crooked knee up to 90º); DJ – vertical jump from 40 cm platform (sit up to 90º); SJ – vertical jump from a static starting position (sit up to 90º). Research timing: November – December (2004) and March (2006). The variability of movement by making vertical jumps in different ways is the main point of this study. To measure the level of spring the contact platform was used. It was connected with the electronic meter of spring that measured spring’s height and take–off time. Sportsmens springs results were recorded into the individual springs protocol. Using the methods of statistical mathematics the results of research were treated. Main tasks: determinate variability of jumps before and after strain, also determinate feetback information and compare variability of movement during this tests. The thirst 5 jumps made were better at the beginning than at the end. The difference is unreliable (accordingly CMJ – 38.4 ± 1.4 and 38.3 ± 1.4 cm.; DJ – 38.6 �� 1.5 and 37.0 ± 1.3 cm.; SJ – 37.6 ± 1.2 and 36.4 ± 1.1 cm., p>0.05). After 10 jumps (with/without feetback information) before strain were: best in SJ (according 18.9 ± 0.7 and 18.8 ± 2.0 cm, p>0.05), worst DJ (according to feetback information 20.7 ± 2.8 and without it – 21.7 ± 2.2 cm.., p>0.05). After 50 jumps sportsmen made 10 jumps without feetback... [to full text]