@article{HowardGranacherBehm2015,
  author    = {Howard, Joshua and Granacher, Urs and Behm, David George},
  title     = {Trunk extensor fatigue decreases jump height similarly under stable and unstable conditions with experienced jumpers},
  series = {European journal of applied physiology},
  volume    = {115},
  journal   = {European journal of applied physiology},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {1439-6319},
  doi       = {10.1007/s00421-014-3011-x},
  pages     = {285 -- 294},
  year      = {2015},
  abstract  = {The purpose of this study was to investigate the effects of back extensor fatigue on performance measures and electromyographic (EMG) activity of leg and trunk muscles during jumping on stable and unstable surfaces. Before and after a modified Biering-Sorensen fatigue protocol for the back extensors, countermovement (CMJ) and lateral jumps (LJ) were performed on a force plate under stable and unstable (balance pad on the force plate) conditions. Performance measures for LJ (contact time) and CMJ height and leg and trunk muscles EMG activity were tested in 14 male experienced jumpers during 2 time intervals for CMJ (braking phase, push-off phase) and 5 intervals for LJ (-30 to 0, 0-30, 30-60, 60-90, and 90-120 ms) in non-fatigued and fatigued conditions. A significant main effect of test (fatigue) (p = 0.007, f = 0.57) was observed for CMJ height. EMG analysis showed a significant fatigue-induced decrease in biceps femoris and gastrocnemius activity with CMJ (p = 0.008, f = 0.58 andp = 0.04, f = 0.422, respectively). LJ contact time was not affected by fatigue or surface interaction. EMG activity was significantly lower in the tibialis anterior with LJ following fatigue (p = 0.05, f = 0.405). A test x surface (p = 0.04, f = 0.438) interaction revealed that the non-fatigued unstable CMJ gastrocnemius EMG activity was lower than the non-fatigued stable condition during the onset-of-force phase. The findings revealed that fatiguing the trunk negatively impacts CMJ height and muscle activity during the performance of CMJs. However, skilled jumpers are not additionally affected by a moderately unstable surface as compared to a stable surface.},
  language  = {en}
}
@article{PrieskeMuehlbauerKruegeretal.2015,
  author    = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Kibele, A. and Behm, David George and Granacher, Urs},
  title     = {Sex-Specific effects of surface instability on drop jump and landing biomechanics},
  series = {International journal of sports medicine},
  volume    = {36},
  journal   = {International journal of sports medicine},
  number    = {1},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0034-1384549},
  pages     = {75 -- 81},
  year      = {2015},
  abstract  = {This study investigated sex-specific effects of surface instability on kinetics and lower extremity kinematics during drop jumping and landing. Ground reaction forces as well as knee valgus and flexion angles were tested in 14 males (age: 23 +/- 2 years) and 14 females (age: 24 +/- 3 years) when jumping and landing on stable and unstable surfaces. Jump height was found to be significantly lower (9 \%, p < 0.001) when drop jumps were performed on unstable vs. stable surface. Significantly higher peak ground reaction forces were observed when jumping was performed on unstable vs. stable surfaces (5 \%, p = 0.022). Regarding frontal plane kinematics during jumping and landing, knee valgus angles were higher on unstable compared to stable surfaces (1932 \%, p < 0.05). Additionally, at the onset of ground contact during landings, females showed higher knee valgus angles than males (222 \%, p = 0.027). Sagittal plane kinematics indicated significantly smaller knee flexion angles (6-35 \%, p < 0.05) when jumping and landing on unstable vs. stable surfaces. During drop jumps and landings, women showed smaller knee flexion angles at ground contact compared to men (27-33 \%, p < 0.05). These findings imply that knee motion strategies were modified by surface instability and sex during drop jumps and landings.},
  language  = {en}
}
@misc{HortobagyiLesinskiGaebleretal.2015,
  author    = {Hortob{\´a}gyi, Tibor and Lesinski, Melanie and G{\"a}bler, Martijn and VanSwearingen, Jessie M. and Malatesta, Davide and Granacher, Urs},
  title     = {Effects of three types of exercise interventions on healthy old adults' gait speed},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43115},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431150},
  pages     = {17},
  year      = {2015},
  abstract  = {Background: Habitual walking speed predicts many clinical conditions later in life, but it declines with age. However, which particular exercise intervention can minimize the age-related gait speed loss is unclear. Purpose: Our objective was to determine the effects of strength, power, coordination, and multimodal exercise training on healthy old adults' habitual and fast gait speed. Methods: We performed a computerized systematic literature search in PubMed and Web of Knowledge from January 1984 up to December 2014. Search terms included 'Resistance training', 'power training', 'coordination training', 'multimodal training', and 'gait speed (outcome term). Inclusion criteria were articles available in full text, publication period over past 30 years, human species, journal articles, clinical trials, randomized controlled trials, English as publication language, and subject age C65 years. The methodological quality of all eligible intervention studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. We computed weighted average standardized mean differences of the intervention-induced adaptations in gait speed using a random-effects model and tested for overall and individual intervention effects relative to no-exercise controls. Results: A total of 42 studies (mean PEDro score of 5.0 +/- 1.2) were included in the analyses (2495 healthy old adults; age 74.2 years [64.4-82.7]; body mass 69.9 +/- 4.9 kg, height 1.64 +/- 0.05 m, body mass index 26.4 +/- 1.9 kg/m(2), and gait speed 1.22 +/- 0.18 m/s). The search identified only one power training study, therefore the subsequent analyses focused only on the effects of resistance, coordination, and multimodal training on gait speed. The three types of intervention improved gait speed in the three experimental groups combined (n = 1297) by 0.10 m/s (+/- 0.12) or 8.4 \% (+/- 9.7), with a large effect size (ES) of 0.84. Resistance (24 studies; n = 613; 0.11 m/s; 9.3 \%; ES: 0.84), coordination (eight studies, n = 198; 0.09 m/s; 7.6 \%; ES: 0.76), and multimodal training (19 studies; n = 486; 0.09 m/s; 8.4 \%, ES: 0.86) increased gait speed statistically and similarly. Conclusions: Commonly used exercise interventions can functionally and clinically increase habitual and fast gait speed and help slow the loss of gait speed or delay its onset.},
  language  = {en}
}
@misc{HortobagyiLesinskiFernandez‐del‐Olmoetal.2015,
  author    = {Hortob{\´a}gyi, Tibor and Lesinski, Melanie and Fernandez-del-Olmo, Miguel and Granacher, Urs},
  title     = {Small and inconsistent effects of whole body vibration on athletic performance},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {627},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43199},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431993},
  pages     = {23},
  year      = {2015},
  abstract  = {Purpose We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Methods Systematic literature review and meta-analysis. Results Whole body vibration combined with exercise had an overall 0.3 \% acute effect on maximal voluntary leg force (-6.4 \%, effect size = -0.43, 1 study), leg power (4.7 \%, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 \%, effect size = -0.12 to 0.22, 2 studies), and athletic performance (-1.9 \%, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 \% chronic effect on maximal voluntary leg force (14.6 \%, weighted mean effect size = 0.44, 5 studies), leg power (10.7 \%, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 \%, effect size = 0.57 to 0.61, 2 studies), and athletic performance (-1.2 \%, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44). Conclusions Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance.},
  language  = {en}
}
@misc{HortobagyiLesinskiFernandezdelOlmoetal.2015,
  author    = {Hortobagyi, Tibor and Lesinski, Melanie and Fernandez-del-Olmo, Miguel and Granacher, Urs},
  title     = {Small and inconsistent effects of whole body vibration on athletic performance: a systematic review and meta-analysis},
  series = {European journal of applied physiology},
  volume    = {115},
  journal   = {European journal of applied physiology},
  number    = {8},
  publisher = {Springer},
  address   = {New York},
  issn      = {1439-6319},
  doi       = {10.1007/s00421-015-3194-9},
  pages     = {1605 -- 1625},
  year      = {2015},
  abstract  = {We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Systematic literature review and meta-analysis. Whole body vibration combined with exercise had an overall 0.3 \% acute effect on maximal voluntary leg force (-6.4 \%, effect size = -0.43, 1 study), leg power (4.7 \%, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 \%, effect size = -0.12 to 0.22, 2 studies), and athletic performance (-1.9 \%, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 \% chronic effect on maximal voluntary leg force (14.6 \%, weighted mean effect size = 0.44, 5 studies), leg power (10.7 \%, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 \%, effect size = 0.57 to 0.61, 2 studies), and athletic performance (-1.2 \%, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44). Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance.},
  language  = {en}
}
@article{GranacherPrieskeMajewskietal.2015,
  author    = {Granacher, Urs and Prieske, Olaf and Majewski, M. and B{\"u}sch, Dirk and M{\"u}hlbauer, Thomas},
  title     = {The Role of Instability with Plyometric Training in Sub-elite Adolescent Soccer Players},
  series = {International journal of sports medicine},
  volume    = {36},
  journal   = {International journal of sports medicine},
  number    = {5},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0034-1395519},
  pages     = {386 -- 394},
  year      = {2015},
  abstract  = {The purpose of this study was to investigate the effects of plyometric training on stable (SPT) vs. highly unstable surfaces (IPT) on athletic performance in adolescent soccer players. 24 male sub-elite soccer players (age: 15 +/- 1 years) were assigned to 2 groups performing plyometric training for 8 weeks (2 sessions/week, 90min each). The SPT group conducted plyometrics on stable and the IPT group on unstable surfaces. Tests included jump performance (countermovement jump [CMJ] height, drop jump [DJ] height, DJ performance index), sprint time, agility and balance. Statistical analysis revealed significant main effects of time for CMJ height (p<0.01, f=1.44), DJ height (p<0.01, f=0.62), DJ performance index (p<0.05, f=0.60), 0-10-m sprint time (p<0.05, f=0.58), agility (p<0.01, f=1.15) and balance (p<0.05, 0.46f1.36). Additionally, a Training groupxTime interaction was found for CMJ height (p<0.01, f=0.66) in favor of the SPT group. Following 8 weeks of training, similar improvements in speed, agility and balance were observed in the IPT and SPT groups. However, the performance of IPT appears to be less effective for increasing CMJ height compared to SPT. It is thus recommended that coaches use SPT if the goal is to improve jump performance.},
  language  = {en}
}
@article{PrieskeMuehlbauerKruegeretal.2015,
  author    = {Prieske, Olaf and M{\"u}hlbauer, Thomas and Kr{\"u}ger, Tom and Kibele, Armin and Behm, David George and Granacher, Urs},
  title     = {Role of the trunk during drop jumps on stable and unstable surfaces},
  series = {European journal of applied physiology},
  volume    = {115},
  journal   = {European journal of applied physiology},
  number    = {1},
  publisher = {Springer},
  address   = {New York},
  issn      = {1439-6319},
  doi       = {10.1007/s00421-014-3004-9},
  pages     = {139 -- 146},
  year      = {2015},
  abstract  = {The present study investigated associations between trunk muscle strength, jump performance, and lower limb kinematics during drop jumps on stable and unstable surfaces. Next to this behavioral approach, correlations were also computed on a neuromuscular level between trunk and leg muscle activity during the same test conditions. Twenty-nine healthy and physically active subjects (age 23 +/- A 3 years) were enrolled in this study. Peak isokinetic torque (PIT) of the trunk flexors and extensors was assessed separately on an isokinetic device. In addition, tests included drop jumps (DJ) on a force plate under stable and unstable (i.e., balance pad on top of the force plate) surfaces. Lower limb kinematics as well as electromyographic activity of selected trunk and leg muscles were analyzed. Significant positive but small correlations (0.50 a parts per thousand currency sign r a parts per thousand currency sign 0.66, p < 0.05) were detected between trunk extensor PIT and athletic performance measures (i.e., DJ height, DJ performance index), irrespective of surface condition. Further, significant negative but small correlation coefficients were examined between trunk extensor PIT and knee valgus motion under stable and unstable surface conditions (-0.48 a parts per thousand currency sign r a parts per thousand currency sign -0.45, p < 0.05). In addition, significant positive but small correlations (0.45 a parts per thousand currency sign r a parts per thousand currency sign 0.68, p < 0.05) were found between trunk and leg muscle activity, irrespective of surface condition. Behavioral and neuromuscular data from this study indicate that, irrespective of the surface condition (i.e., jumping on stable or unstable ground), the trunk plays a minor role for leg muscle performance/activity during DJ. This implies only limited effects of trunk muscle strengthening on jump performance in the stretch-shortening cycle.},
  language  = {en}
}
@misc{BeurskensMuehlbauerGranacher2015,
  author    = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Granacher, Urs},
  title     = {Association of dual-task walking performance and leg muscle quality in healthy children},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-75100},
  pages     = {7},
  year      = {2015},
  abstract  = {Background Previous literature mainly introduced cognitive functions to explain performance decrements in dual-task walking, i.e., changes in dual-task locomotion are attributed to limited cognitive information processing capacities. In this study, we enlarge existing literature and investigate whether leg muscular capacity plays an additional role in children's dual-task walking performance. Methods To this end, we had prepubescent children (mean age: 8.7 ± 0.5 years, age range: 7-9 years) walk in single task (ST) and while concurrently conducting an arithmetic subtraction task (DT). Additionally, leg lean tissue mass was assessed. Results Findings show that both, boys and girls, significantly decrease their gait velocity (f = 0.73), stride length (f = 0.62) and cadence (f = 0.68) and increase the variability thereof (f = 0.20-0.63) during DT compared to ST. Furthermore, stepwise regressions indicate that leg lean tissue mass is closely associated with step time and the variability thereof during DT (R2 = 0.44, p = 0.009). These associations between gait measures and leg lean tissue mass could not be observed for ST (R2 = 0.17, p = 0.19). Conclusion We were able to show a potential link between leg muscular capacities and DT walking performance in children. We interpret these findings as evidence that higher leg muscle mass in children may mitigate the impact of a cognitive interference task on DT walking performance by inducing enhanced gait stability.},
  language  = {en}
}
@article{BeurskensMuehlbauerGranacher2015,
  author    = {Beurskens, Rainer and M{\"u}hlbauer, Thomas and Granacher, Urs},
  title     = {Association of dual-task walking performance and leg muscle quality in healthy children},
  series = {BMC pediatrics},
  volume    = {15},
  journal   = {BMC pediatrics},
  number    = {2},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2431},
  doi       = {10.1186/s12887-015-0317-8},
  year      = {2015},
  abstract  = {Background Previous literature mainly introduced cognitive functions to explain performance decrements in dual-task walking, i.e., changes in dual-task locomotion are attributed to limited cognitive information processing capacities. In this study, we enlarge existing literature and investigate whether leg muscular capacity plays an additional role in children's dual-task walking performance. Methods To this end, we had prepubescent children (mean age: 8.7 ± 0.5 years, age range: 7-9 years) walk in single task (ST) and while concurrently conducting an arithmetic subtraction task (DT). Additionally, leg lean tissue mass was assessed. Results Findings show that both, boys and girls, significantly decrease their gait velocity (f = 0.73), stride length (f = 0.62) and cadence (f = 0.68) and increase the variability thereof (f = 0.20-0.63) during DT compared to ST. Furthermore, stepwise regressions indicate that leg lean tissue mass is closely associated with step time and the variability thereof during DT (R2 = 0.44, p = 0.009). These associations between gait measures and leg lean tissue mass could not be observed for ST (R2 = 0.17, p = 0.19). Conclusion We were able to show a potential link between leg muscular capacities and DT walking performance in children. We interpret these findings as evidence that higher leg muscle mass in children may mitigate the impact of a cognitive interference task on DT walking performance by inducing enhanced gait stability.},
  language  = {en}
}
@misc{GolleMuehlbauerWicketal.2015,
  author    = {Golle, Kathleen and M{\"u}hlbauer, Thomas and Wick, Ditmar and Granacher, Urs},
  title     = {Physical Fitness Percentiles of German Children Aged 9-12 Years},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86613},
  year      = {2015},
  abstract  = {Background Generating percentile values is helpful for the identification of children with specific fitness characteristics (i.e., low or high fitness level) to set appropriate fitness goals (i.e., fitness/health promotion and/or long-term youth athlete development). Thus, the aim of this longitudinal study was to assess physical fitness development in healthy children aged 9-12 years and to compute sex- and age-specific percentile values. Methods Two-hundred and forty children (88 girls, 152 boys) participated in this study and were tested for their physical fitness. Physical fitness was assessed using the 50-m sprint test (i.e., speed), the 1-kg ball push test, the triple hop test (i.e., upper- and lower- extremity muscular power), the stand-and-reach test (i.e., flexibility), the star run test (i.e., agility), and the 9-min run test (i.e., endurance). Age- and sex-specific percentile values (i.e., P10 to P90) were generated using the Lambda, Mu, and Sigma method. Adjusted (for change in body weight, height, and baseline performance) age- and sex-differences as well as the interactions thereof were expressed by calculating effect sizes (Cohen's d). Results Significant main effects of Age were detected for all physical fitness tests (d = 0.40-1.34), whereas significant main effects of Sex were found for upper-extremity muscular power (d = 0.55), flexibility (d = 0.81), agility (d = 0.44), and endurance (d = 0.32) only. Further, significant Sex by Age interactions were observed for upper-extremity muscular power (d = 0.36), flexibility (d = 0.61), and agility (d = 0.27) in favor of girls. Both, linear and curvilinear shaped curves were found for percentile values across the fitness tests. Accelerated (curvilinear) improvements were observed for upper-extremity muscular power (boys: 10-11 yrs; girls: 9-11 yrs), agility (boys: 9-10 yrs; girls: 9-11 yrs), and endurance (boys: 9-10 yrs; girls: 9-10 yrs). Tabulated percentiles for the 9-min run test indicated that running distances between 1,407-1,507 m, 1,479-1,597 m, 1,423-1,654 m, and 1,433-1,666 m in 9- to 12-year-old boys and 1,262-1,362 m, 1,329-1,434 m, 1,392-1,501 m, and 1,415-1,526 m in 9- to 12-year-old girls correspond to a "medium" fitness level (i.e., P40 to P60) in this population. Conclusions The observed differences in physical fitness development between boys and girls illustrate that age- and sex-specific maturational processes might have an impact on the fitness status of healthy children. Our statistical analyses revealed linear (e.g., lower-extremity muscular power) and curvilinear (e.g., agility) models of fitness improvement with age which is indicative of timed and capacity-specific fitness development pattern during childhood. Lastly, the provided age- and sex-specific percentile values can be used by coaches for talent identification and by teachers for rating/grading of children's motor performance.},
  language  = {en}
}