Objectives: The primary purpose of this study was to examine the difference in peak force (PF) production with and without the inclusion of lifting straps (LS) during an isometric mid-thigh pull (IMTP). An additional goal of this study was to identify potential asymmetry during the two protocols while evaluating the potential use of a dual force plate IMTP as a tool for player monitoring programs. Methods: Twenty-one NCAA division I men (n=10) and women (n=11) soccer players performed a maximal IMTP over dual force plates with and without the assistance of LS. The PF total between the two plates for both conditions was used to examine the effect of LS. Asymmetry was assessed by the PF of the separate force plates by calculation of a symmetry index (SI). Results: The PF achieved with the assistance of LS was significantly greater for males (strapped: 2102.3±506.2N, unstrapped: 1468.6±286.0N; p 1105.0±294.7N, unstrapped: 940.6±155.7N; pConclusion: The inclusion of LS on the IMTP allowed for a significantly greater PF production for male and female soccer athletes. However, the increase in PF with the inclusion of LS was greater in the males who saw a large effect size (d=1.959, pp=0.024). Both male and female soccer players possessed some level of asymmetry that did increase with the inclusion of LS, but no significant difference was found between conditions.

Bakgrund: Inom flera idrotter såsom fotboll, basket och innebandy är en bra sprintprestation viktigt. Sprintprestation påverkas av många olika faktorer. I litteraturen har det noterats en stark korrelation mellan prestation i vertikala och horisontella hopp och sprintprestation. Dessutom har flera studier påvisat hur prestation i Isometric Mid-Thigh Pull (IMTP), som är en form av test av maximal statisk styrka i ben- och ryggmuskulaturen, har en måttlig eller stark korrelation med sprintprestation. Enligt författarnas kännedom har ingen studie undersökt korrelationen mellan sprintprestation och variablerna hopphöjd, hopplängd, Rate of Force Development (RFD), Relativ Power (RP) samt Peak Force (PF) hos unga manliga innebandyspelare. Syfte: Syftet med studien är att undersöka korrelationen mellan sprintprestation och prestation i IMTP-test och hopprestation hos unga manliga innebandyspelare. Metod: Deltagarna bestod av nio unga manliga innebandyspelare; 16 ± 1 år, 73,2 ± 6,5 kg och 179 ± 7 cm, som genomförde tester bestående av 20-metersprint, stående längdhopp, Countermovement Jump (CMJ) och IMTP. Resultat: Icke-signifikanta måttligt starka korrelationer noterades mellan sprintprestation och hopprestation (hopphöjd i CMJ, r=-0.455, p=0.219; hopplängd i stående längdhopp, r=-0.467, p=0.205; RP (w/kg) i CMJ, r=-0.356, p=0.348). Ingen av de övriga testresultaten (RFD och PF i IMTP-test) korrelerade med sprintprestation. Slutsats: Måttligt starka, icke-signifikanta korrelationer observerades mellan sprintprestation och hopprestation (hopphöjd i CMJ, hopplängd i stående längdhopp, RP (w/kg) i CMJ. Att de måttligt starka sambanden inte blev statistiskt signifikanta beror troligtvis på att studien hade för få deltagare (n=9). Det fanns ingen korrelation mellan sprintprestation och övriga variabler (RFD och PF i IMTP). Framtida forskning inom ämnet bör genomföras på ett större urval för att kunna få resultat med statistisk signifikans. / Background: Within several sports such as football, basketball and floorball sprint performance is an important ability. Sprint performance is influenced by a variety of factors. Previous literature has demonstrated that there may be a strong correlation between performance in vertical and horizontal jumping and sprint performance. In addition, several studies have shown how performance in Isometric Mid-Thigh Pull (IMTP), which is a form of test of maximal static strength in the leg and back muscles, has a moderate or strong correlation with sprint performance. However the authors found no study that has examined the correlation between sprint performance and the variables jump height, jump length, RFD, RP and PF among young male floorball players. Aim: The aim of this study was to examine the correlation between sprint performance and performance in IMTP-test and jump performance among young male floorball players. Method: The participants in this study consisted of 9 young male floorball players; 16 ± 1 years, 73,2 ± 6,5 kg och 179 ± 7 cm, that performed a variety of tests; 20 meter sprint, standing long jump, Countermovement Jump (CMJ) and IMTP. Results: Non-significant moderately correlations were noted between sprint performance and jump performance (jump height in CMJ, r=-0.455, p=0.219; jump length in standing long jump, r=-0.467, p=0.205; RP (w/kg) in CMJ, r=-0.356, p=0.348). None of the other test results (RFD and PF in IMTP-test) correlated with sprint performance. Besides that none of the test results had a correlation with a statistical significance. Conclusion: Moderately strong, non-significant correlations were observed between sprint performance and jump performance (jump height in CMJ, jump length in standing long jump, RP (w/kg) in CMJ). The relatively low number of participants (n=9) in this study may explain why the moderately strong relationships betweeen sprint and jump performance did not become statistically significant. There was no correlation between sprint performance and the other variables (RFD and PF in IMTP). Future research should be conducted on a larger sample in order to obtain results with statistical significance.

Background: Knowledge of the relationship between fat free mass (FFM) and strength capacity is not only useful in athlete coaching, but may also be important in developing clinical strategies for evaluating health in general populations. Sufficient skeletal muscle mass and strength are important factors for health and physical function. Bioelectrical impedance analysis (BIA) is a popular and clinically useful tool for assessing body composition. However, being able to simultaneously estimate whole body muscle strength without having to perform additional tests may prove useful in evaluating an individual’s health and physical function. Aim: The primary purpose of this study was to quantify the association between total body fat free mass percentage (TBFFM%) and relative strength in the isometric midthigh pull test (IMTP) and grip strength (GS) test in a healthy general young Swedish population. A secondary purpose was to investigate if there are any sex differences.  Methods: The design for this study was cross-sectional. The studied sample represented a general Swedish population of healthy young adults. Participants were asked to participate in testing on one occasion. Three tests were used for collecting data: BIA for data on FFM and both IMTP and hand dynamometer grip strength test for data on maximal force production. All tests were performed in the movement lab on Halmstad University campus. Statistical analyses were done using Pearson’s correlation and linear regression analysis. Results: Participants for this study consisted of healthy females (n=18) and males (n=17) aged 19-39. The primary findings of this study are that there are strong correlations between TBFFM% and relative strength (r = 0.621) in the IMTP test as well as relative GS (r = 0.705) on a whole-group level. The correlation between TBFFM% and relative GS was slightly stronger. Categorized by sex, we found strong positive correlations between TBFFM% and relative IMTP (r = 0.551) and relative GS (r = 0.596) for the female group and moderately strong correlations for the male group (relative IMTP r = 0.411; relative GS  r = 0.422).On a whole-group level, every unit increase in TBFFM% increases relative strength in the IMTP by 0.538N/kgBW (β = 0.538) and relative GS by 0.015 kg/kgBW (β = 0.015). Conclusion: TBFFM% was strongly associated with both relative IMTP strength and relative GS where the association was stronger for females than for males. TBFFM% values may be indicative of an individual's strength, which could be of value in a research setting.

Syfte: Syftet för studien var att undersöka om isometric mid-thigh pull (IMTP) tillsammans med (CMJ) kan anses som lämpliga testmetoder för att mäta prestation i hoppförmåga inom parkour/freerunning (PK/FR). Vi undersökte detta genom att mäta traceurers maximala styrka och explosiva styrka i de nedre extremiteterna, för att sedan jämföra resultaten med fysiskt aktiva idrottsstudenter på högskolenivå. Vi undersökte även om IMTP och CMJ korrelerar med varandra. Urval: 23 personer, 11 traceurer och 12 fysiskt aktiva idrottare rekryterades för denna studie. Metod: vi mätte maximal styrka: Peak force (PF) IMTP (N) på kraftplatta och maximal vertikal hopphöjd: CMJ (cm) på IR-matta. Statistisk analys: Shapiro Wilks användes för normalfördelningar, en oberoende tvåvägs Mann-Whitney U t-test användes för att undersöka skillnader mellan grupperna. Två Spearmans- och ett Pearsons korrelationskoefficienttest användes för att undersöka samband mellan IMTP och CMJ. Resultat: PK gruppen var normalfördelad i alla variabler IMTP (N) och CMJ (cm) men kontroll (KTRL) gruppen var ej normalfördelad i CMJ (cm) och gav utslag för IMTP (N). PK gruppen uppnådde ett IMTP (N) medianvärde på: 2269,9 ± 661.72N och CMJ medianvärde på 36.2 ± 7.48 cm. KTRL gruppen uppnådde ett IMTP (N) medianvärde på: 1626.9 ± 501.95N och ett CMJ medianvärde på: 31.8 ± 5.91cm. Ingen statistiskt signifikant skillnad hittades mellan grupperna, men traceurerna visar en trend för ett högre IMTP (N) värde. Ett statistiskt signifikant samband fanns mellan IMTP och CMJ för hela populationen. R-värde = 0.404. R² värde avrundades till 23%. P-värde = 0.031. Inget statistiskt signifikant samband fanns för PK eller KTRL grupperna individuellt. Slutsats: Traceurerna och de fysiskt aktiva högskolestudenterna visade snarlika resultat i maximal styrka och explosiv styrka i denna studie. Resultaten klassificerades som lågpresterande i förhållande till referensvärden från tidigare studier på traditionella idrotter för IMTP och på traceurer i CMJ. Den maximala styrkan från IMTP tycks förklara 23% av hoppförmågan i CMJ vilket kan vara en indikation av betydelse för traceurers prestation. Framtida forskare uppmuntras använda IMTP och CMJ på större populationer för att kartlägga traceurers force-velocity kurvor och/eller inrätta skadepreventiva program för PK/FR. Begrepp: Traceur (FRE) = tracer (ENG), spårare (SWE). Traceur = manlig Parkour utövare. Traceuse = kvinnlig Parkourutövare. PK/FR = Parkour/Freerunning. PK = Studiens Parkour grupp. KTRL = Studiens kontrollgrupp. Countermovement jump (CMJ), (N) = Newton. 1RM = en 100% maximal ansträngd repetition. / Purpose: The aim of the study was to investigate if IMTP together with CMJ can be considered as suitable methods to measure performance in jumping ability in PK/FR. We investigated this by measuring maximal strength and explosive strength of the lower extremities of traceurs and comparing the results with physically active college student athletes. We investigated also if IMTP and CMJ correlate with each other. Recruitment: 23 people, 11 traceurs and 12 psychical active collegial sport athletes were recruited for this study. Method: We measured maximal strength: PF IMTP (N) on force plate and maximal vertical jump height: CMJ (cm) on IR mat. Statistical analysis: Shapiro Wilks was used for normal distribution; an independent two-way Mann-Whitney U t-test was used to examine differences between groups. Linear regression tests with two Spearman's and one Pearson's correlation coefficient tests were used to examine relationships between IMTP and CMJ. R² values were calculated. Results: The PK group was normally distributed in IMTP (N) and CMJ (cm). The KTRL group was not normally distributed in CMJ (cm) and flagged an indication for IMTP (N). The PK group achieved a IMTP (N) median of 2269.9N SD ± 661.72N. And CMJ median of 36.2cm SD ± 7.48cm. The KTRL group achieved a IMTP (N) median of 1626.9N SD ± 501.95N. And a CMJ median of 31.8cm SD ± 5.91cm. No statistically significant differences were found between the groups. But the traceurs showed a trend for a higher IMTP (N) value. A statistically significant relationship was found between IMTP and CMJ for the entire population. R value = 0.404. R² value was rounded to 23%. P-value = 0.031. No statistically significant relationships were found for the PK- or the KTRL groups individually. Conclusion: The traceurs and the physically active college students were similar in maximal- and explosive strength in this study. The results were classified as low performance in comparison to previous studies of traditional sports on IMTP and on traceurs on CMJ. The maximal strength from the IMTP appears to account for 23% of the jumping ability in CMJ which may be an indication of importance for traceurs performance. Future researchers are encouraged to use IMTP and CMJ on larger populations to map force-velocity curves and/or establish injury prevention programs for PK/FR. Concepts: Traceur (FRE) = tracer (ENG), tracker (SWE). Traceur = male Parkour practitioner. Traceuse = female Parkour practitioner. PK/FR = Parkour/Freerunning. PK = The study's Parkour group. KTRL = Study control group. Countermovement jump (CMJ), Isometric mid-thigh pull (IMTP). 1 RM = a 100% maximum effort repetition. / <p>Ämneslärarprogrammet, Specialidrott</p>

Background: Oral contraceptives are common among female athletes. Still, its effects on athletic performance are poorly investigated. Research in the area has increased in recent years. However, the study qualities and designs are often insufficient and with small sample sizes. Women are currently underrepresented in sport research, and to recruit more women in future studies and to facilitate female athletes’ choices about contraceptives, the impact of oral contraceptives on performance must be better understood. Aim: The aim was to investigate whether monophasic, combined oral contraceptive phases affected maximal muscle strength, anaerobic performance and the corresponding blood lactate response, or perceived mental and physical energy level among young women. Method: The study used a cross-over design where six participants were tested on two occasions. The participants were healthy women between 18 and 29 years old who had beenusing monophasic combined oral contraceptives for at least three months prior to the study. No criteria for training level was set. The Isometric mid-thigh pull (N) was used as an indicator ofmaximal muscle strength; and the Wingate anaerobic test (W) measured anaerobic performance and power with corresponding blood lactate levels (mmol/L) measured at 0, 3 and 5 minutes after termination of the test. The participants rated their current physical and mental energy level on both test occasions using a visual analog scale (0-10). Statistical analyses were madeusing Wilcoxon signed-ranked test. Results: Nine participants were recruited, of which six performed tests on both occasions. The participants had a mean (SD) age of 22.3 (1.8) years, a BMI of 23.3 (2.6) and all reached WHO’sphysical activity recommendations. No statistically significant differences in muscle strengthor anaerobic performance were found regarding peak force (p=0.60), peak power (p=0.35) oraverage power (p=0.60) between oral contraceptive phases. Neither were there any differencesin the blood lactate response to the Wingate test directly after (p=0.92), 3 minutes after (p=0.17) or 5 minutes after (p=0.60) the test. No differences in perceived mental energy level (p=0.35)or perceived physical energy level (p=0.17) between oral contraceptive phases were evident. Conclusion: Oral contraceptive phases did not affect maximal muscle strength, anaerobicperformance, blood lactate response or perceived mental or physical energy levels. Accordingly, there is no need to adapt training to oral contraceptive phases and women can berecruited in future research without consideration of oral contraceptive phases.