Introduction: Caffeine has long been used to enhance athletic performance. The research regarding caffeine’s effects on strength and power performance is lacking, especially in female athletes. Purpose: To analyze the acute effects of caffeine on jumping performance and maximal strength in female collegiate athletes. Methods: Eight female collegiate athletes performed two testing sessions separated by one week. Using a double-blind approach, athletes randomly received 6 mg/kg of body mass of caffeine (CAF) or a placebo (PLA). Following 60min of quiet sitting and a standardized warm-up, athletes were tested on measures of squat jump height (SJH) and peak power (SJPP), countermovement jump height (CMJH) and peak power (CMJPP), and isometric mid-thigh pull peak force (IPF) and rate of force development (RFD) on force platforms. Heart rate, systolic blood pressure, diastolic blood pressure, and tympanic temperature were measured at three time points across the testing session. A paired samples t-test with Hedge’s g effect size was used to compare performance results between conditions. A 2 x 3 (condition x time) repeated measures ANOVA was used to analyze changes in physiological measures between and within conditions. Alpha level for all analyses was set at pResults: There were small to moderate differences in SJH (p=0.08, g=0.26), SJPP (p=0.03, g=0.63), CMJH (p=0.004, g=0.27), CMJPP (p=0.18, g=0.20), IPF (p=0.08, g=0.25), and RFD (p=0.22, g=0.40) in favor of caffeine over placebo. Physiological measurements increased similarly across time for both conditions with the exception of SBP, which was greater following caffeine 3 administration compared to placebo (p=0.02). Conclusions: Caffeine ingestion produced small to moderate improvements in jumping performance; however, caffeine failed to significantly affect maximal strength when compared with the placebo. Nonetheless, there was a small increase in IPF and RFD compared to placebo. Therefore, caffeine appears to be an effective ergogenic aid when used to enhance jumping performance and possibly maximal strength in female collegiate athletes.

The purpose of this investigation was to quantify the magnitude of change in maximal strength and jumping abilities over approximately 1, 2, and 3 years of supervised sport and resistance training in National Collegiate Athletic Association (NCAA) division I women's volleyball athletes. This was an exploratory study on a cohort of women's volleyball athletes (n = 29) split into 3 groups based on the length of the time spent in a supervised resistance training program: Group 1 (n = 11): 0.7 ± 0.3 years, group 2 (n = 9): 1.6 ± 0.2 years, and group 3 (n = 9): 2.4 ± 0.6 years. Monitoring tests consisted of standing height (cm), body mass (kg), body fat (%), static jump height (SJH) and countermovement JH (CMJH) with 0-, 11-, and 20-kg loads (cm), and midthigh clean pull isometric peak force (IPF) and allometrically scaled IPF (IPFa) (Nkg 20.67). Increasing trends were observed for all variables from groups 1 to 2 to 3. Statistically greater improvements (p ≤ 0.05) with moderate to large effect sizes were found between groups 1 and 3 for SJH 0 (19.7%, d = 1.35), SJH 11 (23.8%, d = 1.23), SJH 20 (30.6%, d = 1.20), CMJH 11 (22.6%, d = 1.18), IPF (44.4%, d = 1.22), and IPFa (41.2%, d = 1.32). A combination of traditional resistance training exercises and weightlifting variations at various loads, in addition to volleyball practice, seem to be effective at increasing maximal strength by 44% and vertical JH by 20-30% in NCAA division I women's volleyball athletes after about 2.5 years of training. Furthermore, these characteristics can be improved in the absence of additional plyometric training outside normal volleyball-specific practice.

The purpose of this thesis was to observe psychological, physiological, and performance changes to determine when two high-level weightlifters were peaked for a major competition. We addressed this purpose by conducting a two-part case study series with one USA international level female and one USA national level male weightlifter. Both athletes were considered to be peaked on competition day. The results support our hypothesis that jumping performance would be peaked on competition day corresponding with an increased recovery and decreased stress state. However, contrary to our hypothesis, each athlete exhibited small decreases in muscle size leading into the competition relative to baseline values. Further, changes in inflammatory markers were inconsistent for each athlete and were not reduced as hypothesized. Based on our findings, this investigation supports the use of overreaching and tapering for individual strength-power athletes providing insight into underlying psychological and physiological basis for observed changes in performance.

Blocking is highly correlated with team success. The identification of specific techniques that produce a more successful block would be helpful knowledge for coaches and players. This study compared the traditional, swing, and chicken wing arm swings in combination with the running step footwork pattern in order to determine which arm swing enabled athletes to perform a more effective block. The time it took the athletes to get off the ground and get their hands above (vertically) the net was calculated. The distance the hand reached over the net or hand penetration (displacement between the net and finger in the anterior and vertical planes) was also measured. Lastly, jump height was calculated. High-speed videography was used to capture the blocking movements of thirteen female NCAA Division I athletes. Data were analyzed using a repeated measures ANOVA test, pairwise comparison, and co-variate analysis. The chicken wing block arm swing was quickest in getting the athlete off the ground and getting their hands above the net. The swing block was greatest for hand penetration and jump height. These results can help coaches and players decide which arm swing will benefit them most as a blocking team and as individual blockers.

The purpose of this study was to observe physiological metrics relative to training-induced adaptations in conjunction with laboratory- and competition-based performances in a super-heavyweight weightlifter recovering from a meniscus injury. A retrospective analysis was conducted on a collegiate level male weightlifter (23.2 yrs; 131.9 kg; 187.3 cm) over the course of 21-weeks post-meniscus surgery. Body mass, body fat percentage, hydration status, vastus lateralis muscle cross-sectional area, jump performance, and isometric midthigh pull were regularly assessed as part of an ongoing athlete monitoring program. Pre-injury baseline (T0) measurements were collected relative to a major national competition (COMP1). Post-injury measurements took place at the end of sequential training blocks: strength-endurance training block 1 (T1), basic strength block 2 (T2), and transmutation block 3 (T3). The final measurement session (T4) was conducted three-days post-local competition (COMP2). Only statistically significant increases were observed from T0-T4 for muscle CSA (p=0.0367), isometric peak force (pp=0.0367), and rate of force development at 250ms (p=.0367). While non-significant changes were observed for jumping performance, jump height and net impulse did, however, return to baseline. Competition based performances also showed marked improvements from pre-to-post injury via an increase in weightlifting total (3.2%∆, +9kg) and Sinclair score (1.8%∆, +5.3au). Thus, based on these findings, implementing an evidence-based training program along with a sound athlete monitoring protocol can aid with reducing an athlete’s return-to-train timeline while improving physiological, laboratory- and competition-based performance outcomes.

Training load monitoring is crucial to examine fatigue status. The currently available methodsshow diverse validity, and each come with their limitations. The advantages of CMJ are manyand seem to be useful within team sports, although its use on endurance athletes needs moreresearch. Using force plates is agreed to be the best method, but the uncertainty of whichvariables to use when monitoring fatigue creates difficulties, yet currently, no optimal methodis identified. The purpose of this study was to investigate the use of CMJ and its variables onendurance athletes. Ten triathletes participated in the study, performing the CMJ two times aweek for five weeks. The training load from each session was quantified using Lucia’sTRIMP. A correlation analysis between total TRIMP three days prior to testing and eightdifferent CMJ-variables were made; jump height-flight time (JH-FT), jump height-impulse(JH-IM), Reactive Strength Index-flight time (RSI-FT), Reactive Strength Index-impulse(RSI-IM), braking duration (B-DUR), braking impulse (B-IM), propulsive duration (P-DUR),propulsive impulse (P-IM). A small positive correlation was found between TRIMP and JHFT (r =0.23), JH-IM (r = 0.24), RSI-FT (r = 0.13), and RSI-IM (r = 0.13). B-DUR and B-IMhad a small negative correlation (r = -0.10, r = -0.11) while P-DUR and P-IM showed nocorrelation (r = < 0.02). No significance was found in any correlations (p > 0.05). Resultsindicated that JH may provide better information about fatigue compared to other variables.Variables from the braking phase seem more sensitive to training load compared to thepropulsive phase. Using flight time seems to provide similar results as impulse which couldsimplify fatigue monitoring. However, due to limitations of the study the results should beviewed with caution and more research is needed for further conclusions.Keywords; Jump height, Reactive Strength Index, Flight time, impulse

This present study was intended to identify the reliability and validity of the Vert™ device when compared to a Switch mat. Vert is a wireless device intended to measure jump count and jump height through an application on a smartphone or tablet and the Switch mat provides jump height using wireless sensors. Jump height is an important factor in many sports such as volleyball and basketball and it is important to have devices that coaches and trainers can use for testing that they can rely on. If this device is found to be valid and reliable, coaches and trainers could potentially use it in more practical settings such as practice and games due to the portability and small size. This study consisted of 6 subjects who volunteered. The switch mat was connected to the device to display the jump height immediately after the jump. The Vert sensor was clipped onto the subject’s hip near the center of mass and the jump count and height were then displayed on an app. The subjects completed a series of warm-ups followed by 3 sets of 5 repetition countermovement jumps while using both devices to collect the data. The total 15 jump heights from these 3 sets of 5 were then analyzed using Pearson correlation analysis as well as a paired sample T-test. The jump height recorded from the Vert was consistently about 10 cm off from the jump height of the switch mat, which for a volleyball player, could be the difference between blocking and missing the ball. The results of this study showed that the Vert device is reliable but not practically valid. If technical improvements were made to the device to correct the height components the device could potentially be used in place of a force plate or switch mat when conducting athlete testing but the device is not currently valid for practical use.

The purpose of this study was to examine changes in muscle architecture and jumping performance in NCAA division I women's volleyball players throughout a competitive season and in preparation for conference championships. Ten women volleyball players were tested at preseason (T1), pretaper (T2), and post-taper (T3) on measures of vastus lateralis muscle thickness (MT), pennation angle (PA) and fascicle length (FL) using ultrasonography, and unloaded and loaded squat jump height (SJH) and peak power allometrically scaled to body mass (SJPPa) on a force platform. Rating of perceived exertion training load and strength training volume load were monitored weekly. Player's MT (p < 0.001, Glass's Δ = 2.8) and PA increased (p = 0.02, Δ = 3.9) after in-season training. However, MT decreased after the taper (p = 0.01, Δ = 0.6) but remained elevated above preseason values (p < 0.001, Δ = 1.7). There were no statistical changes in FL, SJH, or SJPPa. Large-to-very large negative relationships (r = −0.51 to −0.81) were observed between preseason relative maximal strength and changes in SJH and SJPPa with various loads over the season. These findings demonstrate that relatively low volumes of strength training and concurrent sport training during a tapering period are capable of preserving jumping performance, but not MT in women's volleyball players; however, jumping performance changes seem to be related to the player's strength level. Stronger players may benefit from an overreaching microcycle before the taper to preserve previously accrued muscular adaptations and jumping performance.

The purpose of this analysis was to construct a preliminary scale of reference values for reactive strength index-modified (RSImod). Countermovement jump data from 151 National Collegiate Athletic Association (NCAA) Division I collegiate athletes (male n = 76; female n = 75) were analyzed. Using percentiles, scales for both male and female samples were constructed. For further analysis, athletes were separated into four performance groups based on RSImod and comparisons of jump height (JH), and time to takeoff (TTT) were performed. RSImod values ranged from 0.208 to 0.704 and 0.135 to 0.553 in males and females, respectively. Males had greater RSImod (p < 0.001, d = 1.15) and JH (p < 0.001, d = 1.41) as compared to females. No statistically significant difference was observed for TTT between males and females (p = 0.909, d = 0.02). Only JH was found to be statistically different between all performance groups. For TTT no statistical differences were observed when comparing the top two and middle two groups for males and top two, bottom two, and middle two groups for females. Similarities in TTT between sexes and across performance groups suggests JH is a primary factor contributing to differences in RSImod. The results of this analysis provide practitioners with additional insight as well as a scale of reference values for evaluating RSImod scores in collegiate athletes.

Introduktion: Smartphoneapplikationen My Jump2 har bedömts att ha större tillgänglighet och inte vara beroende av labbutrustning vid vertikala hopptester. I jämförelse med kraftplatta (golden standard) har applikationen visat sig valid och reliabel. My Jump2 har uppvisat mycket bra- perfekt korrelation mot övrig kraftutrustning. Jämförelse mellan My Jump2 och kliniska tester är ännu inte beprövat på detta område. Syfte: Syftet med denna kliniska studie var att analysera samband och korrelationer mellan värden från My Jump2 och kliniska tester gällande funktionell bedömning av underbenets muskulatur. Därför jämfördes värden hos aktiva, icke skadade män och kvinnor. Metod: Totalt 26st kvinnor och män testades vid ett indivduellt testtilfälle i gymmiljö. 3rep MAX, lunge-test, antal tåhävningar och bäst av tre drop jump analyserades på dominanta benet. Pearsons korrelation användes för att undersöka samband mellan My Jump2 och kliniska tester och ANCOVA för att undersöka skillnader mellan deltagare. Resultat: Huvudfynden var att MyJump2 uppvisade två signifikanta korrelationssamband för männen och ett för kvinnorna vid jämförelse med kliniska tester. Signifikanta skillnader gällande RSI-värde med hänsyn till muskelstyrka 3rep MAX (95% CI; 0,01-0,19, p = 0,03) fanns mellan könen. Ingen signifikant skillnad i stiffness med hänsyn till ROM (95% CI; -0,11- 0,55, p = 0,18) justerat mot kön (95% CI; -0,78-2,03, p = 0,37) återfanns. Konklusion: Resultaten indikerar på att vidare forskning är nödvändig. Endast få signifikanta korrelationssamband återfanns mellan värden från My Jump2 och kliniska tester. My Jump2 visar signifikanta nivåer för RSI-värdet med hänsyn till muskelstyrka och kön. Studien kan inte bekräfta förväntade samband mellan My Jump2 och kliniska tester för underbenet. / Introduction: The smartphoneapplication My Jump2 has been assessed in rescent research for its validity and reliability. In comparison to golden standard devices, My Jump2 shows great- perfect correlation measuring jump height. Eventhough former results indicate usability of the smarthphoneapplication, further research is needed in order to evaluate clinical usefulness in a more expanded population. Aim: The aim of this study was to analyse the relationship and correlations between measured values from My Jump2 and clinical testing of lower extremity performance. This in an active and recreational population, both male and female. Method: A total of 26 males and females were tested individually in a gym-location. 3rep MAX, lunge-test, heel-rises to exhaustion and best of three drop jumps were analysed on the dominat leg. Pearsons correlation was used to evaluate the relationship between My Jump2 and clinical tests and ANCOVA to analyse diffrences within the testgroup. Results: Analysis showed two significant correlations between functional values for the men and one for women when comparing My Jump2 and clinical tests. A significant difference in RSI-value was found between the covariate (sex) (95% CI; 0,01-0,19, p = 0,03) considering 3rep MAX (factor). No significant difference was found in stiffness between the covariate (sex) considering ROM (factor). Conclusion: This study indicates that further research is needed. Analysis shows few significant correlations between My Jump2 and clinical tests. My Jump2 results shows significant values regarding RSI-values considering sex and musclestrenght. This study can not confirm the relationship and correlations between measured values from My Jump2 and clinical testing of lower extremity performance.