Background: Post activation potentiation (PAP) is an increased muscular performance thatoccurs after maximal voluntary contraction. Previous studies have shown a significantincrease in explosive movements, such as sprint and jump performance, as an effect ofthese maximal contractions. Aim: The aim of this study was to analyze if PAP, in terms of heavy squats, has aperformance enhancing effect on 30 meter sprint, with a hypothesis that the maximal effortin the squat has a performance enhancing effect on 30 meter sprint. Method: Twelve healthy male Crossfit athletes from Crossfit Halmstad, age between x-x,volunteered to participate in the study, eleven of these completed all of the test sessions in thiscross-sectional study. During the first test session, the subjects attempted to set a onerepetition max (1RM) in the back squat. During the second and third test session, the subjectswere randomly divided into two groups and the subjects got to perform both the non-PAP andthe PAP protocol during different sessions, depending on which group they were in. Thesprint time was measured with a handheld stopwatch. Wilcoxon Signed Rank Test was usedto determine significant differences between sprint time after the two different protocols, andthe level of significance was set at p < 0.05. Result: The result showed that there was no significant difference between PAP and non-PAPprotocols (p = 0,679). With a median value of 4,78 seconds, a minimum value of 4,59seconds and a maximum value of 5,54 seconds for the sprint trials after PAP and a medianvalue of 4,82 seconds, a minimum value of 4,59 seconds and a maximum value of 5,31seconds for the sprint trials without PAP, the results did not confirm the hypothesis. Conclusion: As an effect from the low number of participants, the result could be deceptive.The study could have show a different result if the number of participants would exceed atleast 25 subjects. There are no performance enhancing effects in the sprint after PAP, in thisstudy. Further research is required, to determine possible performance enhancing effectsfrom PAP.

A traditional warm-up (WU) for track sprinters usually includes a general WU, a series of mobility drills and some short sprint strides lasting 30-60 min in total. A WU of this duration might cause significant fatigue and impair sprint performance. Aim: To test the hypothesis that a traditional high intense warm-up of long duration would elicit fatigue and impair sprint performance. Methods: Five highly trained males competitive in endurance sports performed three different WU protocols on separate days in their postseason period. Their mean ± SD age, body mass and height were 24.2 ± 1.6 years, 78.4 ± 7.8 kg, 179.6 ± 8.8 cm. The study participants performed a timed 60 meter sprint on an indoor track. The traditional warm-up (LONG), started with 10 min of easy running; then 7 min of mobility drills followed by five sprints performed with 3-min break in between. The total duration of LONG was 35 minutes. The experimental warm-up (SHORT) was shorter and less intense; 10 min of easy running was followed by just one sprint. Both warm-up protocols were followed by 10 min of recovery, where participants were not allowed to sit down. A third test occasion served as control (CON), where participants did not conduct physical activity prior to the time trial, only 10 min of recovery. Participants also rated the satisfaction of their performance on a 10 point scale. Results: The results of 60 m time trial performance showed no significant differences among the different WU protocols (P = 0.20). The 60 m performance was better for SHORT (8.02 ± 0.10 sec) than for LONG (8.08 ± 0.16 sec) and CON (8.20 ± 0.21 sec). 4 of 5 participants experienced their fastest time trial following SHORT. It appeared that participants were significantly faster following SHORT (7.99 ± 0.22 ms-1) compared to LONG (7.77 ± 0.33 ms-1) in the final 10 m of the time trial (P = 0.05). The satisfaction after SHORT scored highest (6.9), followed by LONG (5.9) and CON (4.5). Conclusions: There is no significant difference between a traditional WU compared to a WU of shorter duration and lower intensity. The traditional WU showed a significant decline in running speed in the final stage of the time trial, which might be caused by fatigue.

No description available.

Abstract available in the Journal of Strength and Conditioning Research

Bakgrund: Syftet med denna studie var att undersöka effekten av sju dagars tillskott av betain (2,5 gram/dag) på prestationsförmågan i idrottsspecifika tester för manliga vältränade cykelatleter. Metod: Sex (n=6) manliga testpersoner (genomsnitt ± standardavvikelse ålder, 31,7 ± 10,2 år; längd, 188,2 ± 3,6 cm; kroppsvikt; 82,5 ± 7,6 kg; fettfri massa, 71,6 ± 7,3 kg) genomförde förtester bestående av fem counter movement jumps, fyra stycken 12 s wingate-sprinter med 2,5 minuters aktiv vila följt av fem ytterligare counter movement jumps. De blev sedan indelade slumpmässigt i betain- eller placebogrupper. Första testet etablerade basvärden och eftertest ”1” samt ”2” föregicks med antingen sju dagars tillskott med placebo (2,5 g maltodextrin plus 12,5 mg riboflavin) eller betain (2,5 g trimetylglycin plus 12,5 mg riboflavin). Riboflavin användes för att undanröja den fiskliknande doften som kan uppstå vid tillskott av betain. Doseringen bestod av fyra kapslar per dag till måltid, varav två kapslar intogs på morgonen eller förmiddagen (före träning) och två kapslar intogs på eftermiddagen eller kvällen (efter träning). Vi använde oss av en dubbelblindad, kontrollerad randomisering cross-over design; med en veckas washout mellan placebo och betain. Maximum Peak Power, Average Peak Power, Maximum Average Power, Mean Average Power, Mean Relative Power Drop, Maximum Relative Power Drop, CMJ-Medel och CMJ-Max före och efter sprinterna analyserades med two-tailed t-test 2 och 3 för att jämföra skillnader före och efter intag av tillskott samt skillnaderna mellan grupperna.Resultat: Inga signifikanta skillnader kunde noteras. Konklusion: En veckas tillskott av betain gav inte någon signifikant förbättring jämfört med placebo i hopp- och sprintförmåga samt förmåga att ta ut sig själv maximalt hos aktiva cyklister. Fler studier med framförallt större testgrupper efterlyses för att utvärdera betainets ergogena effekt bland aktiva atleter. / The effect of betaine supplementation on counter movement jumps and sprint performance among male bicycle athletes Background: The purpose of this study was to investigate the effect of a seven days supplementation regimen with betaine (2,5 grams per day) on counter movement jumps and sprint performance in trained male bicyclists. Method: Six (n=6) male subjects (mean ± standard deviation age, 31,7 ± 10,2 years; height, 188,2 ± 3,6 cm; bodyweight, 82,5 ± 7,6 kg; lean body mass, 71,6 ± 7,6 kg) completed a 21 day study involving five counter movement jumps (no arm swing) followed by 4 consecutive modified 12 second Wingate sprints on a bicycle ergometer with active rest (2,5 minutes) followed by another set of five counter movement jumps. A double blind, controlled randomized cross over design was used and there was a 1 week washout between the supplementation startup for each group. Following pre-testing (baseline) the participants were randomly divided into groups by choosing one of the following supplements: “12” Placebo –2,5 grams of maltodextrine plus 12,5 mg riboflavin or “11” – Active 2,5 grams of trimethylglycine plus 12,5 mg riboflavin. Riboflavin was used so mask the “fishy odor syndrome” effect of high intakes of trimethylglycine that may cause trimethyluria. Daily consumption of capsules was divided into two doses of two capsules each with meals. One dose (two capsules) was consumed in the morning and one dose in the evening. The following variables were analyzed: Maximum Peak Power, Average Peak Power, Maximum Mean Power, Average Mean Power, Maximum Relative Power Drop, Average Relative Power Drop, Mean CMJ-Pre + Post sprints and Maximal CMJ-Pre + Post sprints. Results: None of the parameters showed statistical significance. Conclusion: Our study indicates that seven days of betaine ingestion does not seem significantly improve counter movement jump or sprint capacity in male trained bicyclists. Larger studies are needed to investigate the performance enhancing effects of betaine, especially among high performance athletes.