6 research outputs found
Very Heavy Resisted Sprint Training for Adolescent Football Players : A training intervention on acceleration, sprint and jump performance in late pubertal adolescent athletes
Abstract Aim The main purpose of this study was to investigate and compare the effects of a very heavy resisted sprint training regimen and a unresisted sprint training regimen on sprint, acceleration and jump performance in late pubertal adolescent football (soccer) players at mid- to post-PHV and >95% PAH. Method In total 27 male football players were recruited as volunteer participants. The participants had no previous experience with resisted sprint training. The participants were randomly assigned to either the resisted sprint (RST) (n=9) or unresisted sprint (UST) (n=10) training group. However, the grouping was matched based on the force-velocity (F-v) profiling. A control group (i.e. TAU group n=8) was matched with the experimental groups based on age and anthropometrics. The training was done twice a week for four weeks, consisting of either resisted or unresisted sprints. 24 of the original 27 participants could later be included for statistical analysis. During intervention the TAU group performed the regular team training with no additional stimuli from the researchers. Anthropometrics, sprint, acceleration and jump performance testing was tested pre- and post-training intervention. Results The four-week training intervention resulted in significant improvements of sprint- and acceleration for the RST-group. The improvements were 3,8% (±0.05) in T30, 4,2% (±0.06) in T20, 5,7% (±0.06) in T10, and 7,9% (±0.06) in the T5. The RST and UST groups also had significant improvements in both vertical and horizontal jump performance. Further there were several significant between group changes in both sprint and jump performance favoring the RST group over both the UST and TAU groups. Conclusion The conclusions are that in this population a very heavy RST regimen elicits improvements in sprint and acceleration performance whilst a UST regimen does not. Further, both the RST- and UST- training regimens elicit improvements in both vertical and horizontal jump performance. The improvements of the present study follow the pattern of previous studies in the field indicating a greater horizontal force generating ability. However, the improvements in the present study are larger than previously seen, indicating that this type of training might be extra beneficial to enhance sprint and jump performance in late pubertal adolescent athletes. The findings of the present study also contradict the typical recommendations of using light resistance loads (i.e. the 10% rule) when it comes to RST. Heavier loads, as in this case 103,5% of body weight on average, can indeed be used to produce sprint and acceleration gains in a late pubertal adolescent athlete population. The improvement in these short sprints (5-30m) versus the eventual performance decrease in longer sprints 40-70m (e.g. due to less effective maximal velocity phase) is a trade off which logically should be worthwhile for team sport athletes.Abstrakt Syfte Det huvudsakliga syftet med denna studie var att undersoÌka och jaÌmfoÌra effekterna av vaÌldigt tungt belastad sprinttraÌning och obelastad sprinttraÌning paÌ sprint-, acceleration och hopprestation hos unga fotbollsspelare i sena tonaÌren som ligger paÌ en mognadsgrad av âmid- post-PHVâ samt >95% PAH. Metod Totalt 27 fotbollsspelare rekryterades som frivilliga deltagare. Deltagarna hade ingen tidigare erfarenhet av belastad sprinttraÌning. Deltagarna blev slumpmaÌssigt indelade till antingen den belastade (RST) eller den obelastade (UST) traÌningsgruppen. Dock skedde grupperingen med deltagarnas kraft- hastighetsprofilering som bas, daÌ grupperna blev matchade efter denna. Kontrollgruppen (TAU n=8) matchades med experimentgrupperna efter aÌlder och antropometri. TraÌningen bestod av vaÌldigt tungt belastad eller obelastad sprinttraÌning och utfoÌrdes tvaÌ gaÌnger i veckan under fyra veckor. 24 av de initialt 27 deltagarna kunde inkluderas foÌr vidare analys. Under interventionen genomfoÌrde TAU den vanliga lagtraÌningen utan ytterligare traÌningsstimuli fraÌn forskarna. Antropometri, sprint, acceleration och hopprestation testades foÌre respektive efter interventionen. Resultat Den fyra veckor laÌnga traÌningsinterventionen resulterade i signifikanta foÌrbaÌttringar i sprint och acceleration foÌr RST-gruppen. FoÌrbaÌttringarna var 3,8% (±0.05) i T30, 4,2% (±0.06) i T20, 5,7% (±0.06) i T10, och 7,9% (±0.06) i T5. RST och UST grupperna hade ocksaÌ signifikanta foÌrbaÌttringar i baÌde vertikal och horisontell hopprestation. Vidare fanns det flera signifikanta mellangruppsskillnader i baÌde sprint- och hopprestation till foÌrdel foÌr RST gruppen oÌver baÌde UST och TAU grupperna. Konklusion Konklusionen aÌr att ett vaÌldigt tungt RST-traÌningsprogram framkallar signifikanta foÌrbaÌttringar i baÌde sprint, acceleration och hopprestation medan ett UST-traÌningsprogram inte goÌr det. Vidare kan konkluderas att baÌde ett RST- och ett UST-traÌningsprogram signifikant foÌrbaÌttrar baÌde vertikal och horisontell hopprestationen. FoÌrbaÌttringarna foÌljer moÌnstret fraÌn tidigare studier paÌ omraÌdet och indikerar en stoÌrre horisontell kraftproduktion. Dock aÌr foÌrbaÌttringarna stoÌrre aÌn vad som tidigare observerats vilket indikerar att denna typ av traÌning kan vara extra foÌrtjaÌnstfull foÌr denna population. Resultaten motsaÌger aÌven den typiska rekommendationen kring laÌtta vikter (dvs. 10% regeln) vid belastad sprinttraÌning. Tyngre belastning, som i detta fall i genomsnitt 103,5% av kroppsvikten, kan anvaÌndas foÌr att producera sprint- och accelerationsfoÌrbaÌttringar i denna population. FoÌrbaÌttringen av denna typ av korta sprinter (5-30m) gentemot den eventuella prestationsfoÌrsaÌmringen i laÌngre sprinter (40-70m) torde vara ett byte som aÌr vaÌrt att goÌra foÌr lagidrottare
Physical literacy and physical activity in swedish preschool children â a cross-sectional study
INTRODUCTION:There are substantial evidence for the numerous positive health benefits of physical activity (PA) [1]. At the same time, PA-levels in European and Swedish children are insufficient [2]. Inadequate PA-levels, and associated noncommunicable diseases, are regarded as one of the most significant public health challenges confronting us. Hence, it is important to understand how we can promote ways for children to reach adequate PA-levels. Physical Literacy (PL), a theory with potential benefits for PA-behaviors and health, has garnered increasing attention over the last few years. Encompassing physical, affective, and cognitive dimensions PL is often described as an individualâs capacity, confidence, and motivation to partake- and engage in PA [3]. The early childhood years are suggested for PL promotion since this period is regarded as crucial for PA-behaviors, future health, and the opportunity to reach most children via school settings. However, the assessment and status of PL in young children, specifically in Sweden, is at best scarce. Consequently, research is required to assess PL and its connection to PA-levels in young Swedish children. METHODS:The data for this study will be derived from hip-worn accelerometers (GT3X+, Actigraph) worn for 7 days to assess PA-levels, as well as a modified version of the Canadian Preschool Physical Literacy Assessment to assess PL. The study will include 412 preschool children, aged 3-6, from 20 preschools. The data will be analyzed and presented via descriptive statistics, and multi-level linear regression models will be used to determine associations between total- and intensity stratified PA-levels and PL. RESULTS:Tentatively, the results of this study are expected to provide: 1) a picture of PL and PA in Swedish preschool children and the connection therein; 2) much-needed data for the fields of PL and early childhood research; 3) Indications on effectiveness of PL for promoting PA; and 4) guidance for future research in PL. CONCLUSION:With individual, and public health advancements in mind, there is ample reason to enhance our understanding of the relationship between PL and PA-levels of Swedish preschool children, as well as, adding data to the PL-field. The present study has the potential to contribute to these objectives. References:1. Warburton, D. E., & Bredin, S. S. (2017). Health benefits of physical activity: a systematic review of current systematic reviews. Current opinion in cardiology, 32(5), 541-556.2. Steene-Johannessen J, Hansen BH, Dalene KE, Kolle E, Northstone K, MĂžller NC, et al. Variations in accelerometry measured physical activity and sedentary time across Europe â harmonized analyses of 47,497 children and adolescents. Int J Behav Nutr Phys Act. 2020;17(1):38.3. Edwards, L. C., Bryant, A. S., Keegan, R. J., Morgan, K., & Jones, A. M. (2017). Definitions, foundations and associations of physical literacy: a systematic review. Sports medicine, 47(1), 113-126
Physical literacy and physical activity in swedish preschool children â a cross-sectional study
INTRODUCTION:There are substantial evidence for the numerous positive health benefits of physical activity (PA) [1]. At the same time, PA-levels in European and Swedish children are insufficient [2]. Inadequate PA-levels, and associated noncommunicable diseases, are regarded as one of the most significant public health challenges confronting us. Hence, it is important to understand how we can promote ways for children to reach adequate PA-levels. Physical Literacy (PL), a theory with potential benefits for PA-behaviors and health, has garnered increasing attention over the last few years. Encompassing physical, affective, and cognitive dimensions PL is often described as an individualâs capacity, confidence, and motivation to partake- and engage in PA [3]. The early childhood years are suggested for PL promotion since this period is regarded as crucial for PA-behaviors, future health, and the opportunity to reach most children via school settings. However, the assessment and status of PL in young children, specifically in Sweden, is at best scarce. Consequently, research is required to assess PL and its connection to PA-levels in young Swedish children. METHODS:The data for this study will be derived from hip-worn accelerometers (GT3X+, Actigraph) worn for 7 days to assess PA-levels, as well as a modified version of the Canadian Preschool Physical Literacy Assessment to assess PL. The study will include 412 preschool children, aged 3-6, from 20 preschools. The data will be analyzed and presented via descriptive statistics, and multi-level linear regression models will be used to determine associations between total- and intensity stratified PA-levels and PL. RESULTS:Tentatively, the results of this study are expected to provide: 1) a picture of PL and PA in Swedish preschool children and the connection therein; 2) much-needed data for the fields of PL and early childhood research; 3) Indications on effectiveness of PL for promoting PA; and 4) guidance for future research in PL. CONCLUSION:With individual, and public health advancements in mind, there is ample reason to enhance our understanding of the relationship between PL and PA-levels of Swedish preschool children, as well as, adding data to the PL-field. The present study has the potential to contribute to these objectives. References:1. Warburton, D. E., & Bredin, S. S. (2017). Health benefits of physical activity: a systematic review of current systematic reviews. Current opinion in cardiology, 32(5), 541-556.2. Steene-Johannessen J, Hansen BH, Dalene KE, Kolle E, Northstone K, MĂžller NC, et al. Variations in accelerometry measured physical activity and sedentary time across Europe â harmonized analyses of 47,497 children and adolescents. Int J Behav Nutr Phys Act. 2020;17(1):38.3. Edwards, L. C., Bryant, A. S., Keegan, R. J., Morgan, K., & Jones, A. M. (2017). Definitions, foundations and associations of physical literacy: a systematic review. Sports medicine, 47(1), 113-126
Cross Education; : The effect of 10 weeks of unilateral resistance training on strength and hypertrophy
Abstract   Aim   The main purpose of this study was to investigate Cross Education (CE), and how gender, detraining and leg dominance affects CE in previously untrained subjects when conducting a unilateral resistance training program. We also investigated if unilateral resistance training can give a hypertrophic response.   Method  Twenty healthy previously untrained individuals, 10 females and 10 males, were recruited as volunteer participants. The participants were randomly assigned to train either left or right leg. The training intervention was 10 weeks (34 sessions) of unilateral resistance training in the leg press and leg extension, sixteen of the participants fulfilled the criteria for inclusion. After two initial familiarization the participants trained conventional resistance training three times a week (week 1-3, 5-7 and 9-10) and Blood Flow Restriction Training (BFRT) five times a week (week 4 and 8). One repetition maximum for both legs in the leg press and leg extension was tested pre-, post and post20 to the training intervention as well as ultrasound measurements of muscle thickness.  Results   The ten-week training period resulted in a significant increase of maximal strength for the untrained leg 18,9 %, (16,6) (p < 0,01) in the leg press and 6,7 %, (3,7) (p < 0,05) in the leg extension. When comparisons between gender were made only men had a significant increase 26,5 %, (16,7) (p < 0,01) in the leg press and 9,9 %, (4,7) (p < 0,05) in the leg extension. Also, we saw a significant difference between women and men on a group level. Comparisons of dominant vs non-dominant leg showed that training the dominant leg resulted in a significant increase of maximal strength in the untrained leg in both the leg press 22 %, (17,9) (p < 0,01) and leg extension 10,1 %, (4,3) (p < 0,05). The maximal strength in the untrained leg was not significantly altered by the detraining period and a significant increase of muscle thickness could be seen in the untrained leg at MP50 4,7 %, (1,3) (p < 0,01).  Conclusion   The conclusions are that a ten week unilateral resistance training intervention results in a CE effect for men but not for women and that this type of training also can result in an increased muscle thickness in the untrained leg. Our findings also supports that training the dominant limb has superior effect on achieving a CE effect. Lastly we conclude that a twenty week detraining period did not affect the CE achieved strength.   Abstrakt   Syfte    Studiens huvudsakliga syfte var att undersöka Cross Education (CE) och hur kön, viloperiod och ben-dominans pĂ„verkar CE hos otrĂ€nade individer nĂ€r man undergĂ„r ett unilateralt styrketrĂ€ningsprogram. Vi undersökte Ă€ven om ett unilateral styrketrĂ€ning kunde ge ett hypertrofisvar.   Metod   Tjugo friska otrĂ€nade och för nĂ€rvarande inaktiva individer, tio kvinnor och tio mĂ€n rekryterades som frivilliga deltagare. Deltagarna randomiserades för att trĂ€na antingen vĂ€nster eller höger ben. TrĂ€ningsperioden var tio veckor (trettiofyra pass) av unilateral styrketrĂ€ning i benpress och benspark, sexton deltagare uppfyllde kriterierna för inkludering. TvĂ„ initiala familjĂ€riseringspass hölls varefter trĂ€ningen delades in i tvĂ„ typer av trĂ€ning, dels konventionell styrketrĂ€ning tre gĂ„nger i veckan (vecka 1-3, 5-7 och 9-10) och dels Blood Flow Restriction Training (BFRT) fem gĂ„nger i veckan (vecka 4 och 8). Före, efter och efter tjugo veckor testades one repetition maximum för bĂ„da benen i benpress och benspark samt att ultraljudsmĂ€tningar för muskeltjocklek utfördes.    Resultat   Den tio veckor lĂ„nga trĂ€ningsperioden resulterade i en signifikant ökning av den maximala styrkan för det otrĂ€nade benet 18,9 % (16,6) (p < 0,010) i benpressen och 6,7 % (3,7) (p < 0,050) i bensparken. NĂ€r jĂ€mförelser gjordes mellan könen sĂ„ hade enbart mĂ€n en signifikant ökning, 26,5 % (16,7) (p < 0,010) i benpressen och 9,9 % (4,7) (p < 0,050) i bensparken. Vi fann Ă€ven att det var en signifikant skillnad mellan kvinnor och mĂ€n pĂ„ gruppnivĂ„.  JĂ€mförelser mellan dominant och icke-dominant ben visade att trĂ€ning av det dominanta benet resulterade i en signifikant styrkeökning i bĂ„de benpress 22 % (17,9) (p < 0,010) och benspark 10,1 % (4,3) (p < 0,050). Den maximala styrkan i det otrĂ€nade benet pĂ„verkades inte signifikant av en viloperiod och en signifikant ökning i muskeltjocklek kunde ses i det otrĂ€nade benet i MP50 4,7 % (1,3) (p < 0,010)   Konklusion   Slutsatserna Ă€r att en tio veckors unilateral styrketrĂ€ningsintervention resulterar i en CE effekt hos mĂ€n men inte hos kvinnor, och att denna typ av trĂ€ning kan resultera i en ökad muskeltjocklek i det otrĂ€nade benet. VĂ„ra fynd styrker att trĂ€ning av den dominanta lemmen har större effekt pĂ„ CE. Slutligen drar vi slutsatsen att en tjugo veckors viloperiod inte pĂ„verkar CE-styrkan. Â
Cross Education; : The effect of 10 weeks of unilateral resistance training on strength and hypertrophy
Abstract   Aim   The main purpose of this study was to investigate Cross Education (CE), and how gender, detraining and leg dominance affects CE in previously untrained subjects when conducting a unilateral resistance training program. We also investigated if unilateral resistance training can give a hypertrophic response.   Method  Twenty healthy previously untrained individuals, 10 females and 10 males, were recruited as volunteer participants. The participants were randomly assigned to train either left or right leg. The training intervention was 10 weeks (34 sessions) of unilateral resistance training in the leg press and leg extension, sixteen of the participants fulfilled the criteria for inclusion. After two initial familiarization the participants trained conventional resistance training three times a week (week 1-3, 5-7 and 9-10) and Blood Flow Restriction Training (BFRT) five times a week (week 4 and 8). One repetition maximum for both legs in the leg press and leg extension was tested pre-, post and post20 to the training intervention as well as ultrasound measurements of muscle thickness.  Results   The ten-week training period resulted in a significant increase of maximal strength for the untrained leg 18,9 %, (16,6) (p < 0,01) in the leg press and 6,7 %, (3,7) (p < 0,05) in the leg extension. When comparisons between gender were made only men had a significant increase 26,5 %, (16,7) (p < 0,01) in the leg press and 9,9 %, (4,7) (p < 0,05) in the leg extension. Also, we saw a significant difference between women and men on a group level. Comparisons of dominant vs non-dominant leg showed that training the dominant leg resulted in a significant increase of maximal strength in the untrained leg in both the leg press 22 %, (17,9) (p < 0,01) and leg extension 10,1 %, (4,3) (p < 0,05). The maximal strength in the untrained leg was not significantly altered by the detraining period and a significant increase of muscle thickness could be seen in the untrained leg at MP50 4,7 %, (1,3) (p < 0,01).  Conclusion   The conclusions are that a ten week unilateral resistance training intervention results in a CE effect for men but not for women and that this type of training also can result in an increased muscle thickness in the untrained leg. Our findings also supports that training the dominant limb has superior effect on achieving a CE effect. Lastly we conclude that a twenty week detraining period did not affect the CE achieved strength.   Abstrakt   Syfte    Studiens huvudsakliga syfte var att undersöka Cross Education (CE) och hur kön, viloperiod och ben-dominans pĂ„verkar CE hos otrĂ€nade individer nĂ€r man undergĂ„r ett unilateralt styrketrĂ€ningsprogram. Vi undersökte Ă€ven om ett unilateral styrketrĂ€ning kunde ge ett hypertrofisvar.   Metod   Tjugo friska otrĂ€nade och för nĂ€rvarande inaktiva individer, tio kvinnor och tio mĂ€n rekryterades som frivilliga deltagare. Deltagarna randomiserades för att trĂ€na antingen vĂ€nster eller höger ben. TrĂ€ningsperioden var tio veckor (trettiofyra pass) av unilateral styrketrĂ€ning i benpress och benspark, sexton deltagare uppfyllde kriterierna för inkludering. TvĂ„ initiala familjĂ€riseringspass hölls varefter trĂ€ningen delades in i tvĂ„ typer av trĂ€ning, dels konventionell styrketrĂ€ning tre gĂ„nger i veckan (vecka 1-3, 5-7 och 9-10) och dels Blood Flow Restriction Training (BFRT) fem gĂ„nger i veckan (vecka 4 och 8). Före, efter och efter tjugo veckor testades one repetition maximum för bĂ„da benen i benpress och benspark samt att ultraljudsmĂ€tningar för muskeltjocklek utfördes.    Resultat   Den tio veckor lĂ„nga trĂ€ningsperioden resulterade i en signifikant ökning av den maximala styrkan för det otrĂ€nade benet 18,9 % (16,6) (p < 0,010) i benpressen och 6,7 % (3,7) (p < 0,050) i bensparken. NĂ€r jĂ€mförelser gjordes mellan könen sĂ„ hade enbart mĂ€n en signifikant ökning, 26,5 % (16,7) (p < 0,010) i benpressen och 9,9 % (4,7) (p < 0,050) i bensparken. Vi fann Ă€ven att det var en signifikant skillnad mellan kvinnor och mĂ€n pĂ„ gruppnivĂ„.  JĂ€mförelser mellan dominant och icke-dominant ben visade att trĂ€ning av det dominanta benet resulterade i en signifikant styrkeökning i bĂ„de benpress 22 % (17,9) (p < 0,010) och benspark 10,1 % (4,3) (p < 0,050). Den maximala styrkan i det otrĂ€nade benet pĂ„verkades inte signifikant av en viloperiod och en signifikant ökning i muskeltjocklek kunde ses i det otrĂ€nade benet i MP50 4,7 % (1,3) (p < 0,010)   Konklusion   Slutsatserna Ă€r att en tio veckors unilateral styrketrĂ€ningsintervention resulterar i en CE effekt hos mĂ€n men inte hos kvinnor, och att denna typ av trĂ€ning kan resultera i en ökad muskeltjocklek i det otrĂ€nade benet. VĂ„ra fynd styrker att trĂ€ning av den dominanta lemmen har större effekt pĂ„ CE. Slutligen drar vi slutsatsen att en tjugo veckors viloperiod inte pĂ„verkar CE-styrkan. Â
Four Weeks of Power Optimized Sprint Training Improves Sprint Performance in Adolescent Soccer Players.
PURPOSE: This study compared the effects of heavy resisted sprint training (RST) versus unresisted sprint training (UST) on sprint performance among adolescent soccer players. METHODS: Twenty-four male soccer players (age: 15.7 [0.5]Â y; body height: 175.7 [9.4]Â cm; body mass: 62.5 [9.2]Â kg) were randomly assigned to the RST group (n = 8), the UST group (n = 10), or the control group (n = 6). The UST group performed 8 Ă 20 m unresisted sprints twice weekly for 4 weeks, whereas the RST group performed 5 Ă 20-m heavy resisted sprints with a resistance set to maximize the horizontal power output. The control group performed only ordinary soccer training and match play. Magnitude-based decision and linear regression were used to analyze the data. RESULTS: The RST group improved sprint performances with moderate to large effect sizes (0.76-1.41) across all distances, both within and between groups (>92% beneficial effect likelihood). Conversely, there were no clear improvements in the UST and control groups. The RST evoked the largest improvements over short distances (6%-8%) and was strongly associated with increased maximum horizontal force capacities (r = .9). Players with a preintervention deficit in force capacity appeared to benefit the most from RST. CONCLUSIONS: Four weeks of heavy RST led to superior improvements in short-sprint performance compared with UST among adolescent soccer players. Heavy RST, using a load individually selected to maximize horizontal power, is therefore highly recommended as a method to improve sprint acceleration in youth athletes