TY  - JOUR
A1  - Chaabene, Helmi
A1  - Negra, Yassine
A1  - Capranica, Laura
A1  - Prieske, Olaf
A1  - Granacher, Urs
T1  - A Needs Analysis of Karate Kumite With Recommendations for Performance Testing and Training
JF  - Strength and conditioning journal
N2  - An effective training program needs to be customized to the specific
demands of the redpective sport. Therefore, it is important to
conduct a needs analysis to gain information on the unique
characteristics of the sport. The objectives of thes review were (A)
to conduct a systematic needs analysis of karate kumite and (B) to
provide practical recommendations for sport-specific performance
testing and training of karate kumite athletes.
KW  - sport profile
KW  - striking combat sports
KW  - strength
KW  - power
KW  - energetic systems
KW  - injury
KW  - assessment
Y1  - 2019
U6  - https://doi.org/10.1519/SSC.0000000000000445
SN  - 1524-1602
SN  - 1533-4295
VL  - 41
IS  - 3
SP  - 35
EP  - 46
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Zinke, Fridolin
A1  - Gebel, Arnd
A1  - Granacher, Urs
A1  - Prieske, Olaf
T1  - Acute Effects of Short-Term Local Tendon Vibration on Plantar Flexor Torque, Muscle Contractile Properties, Neuromuscular and Brain Activity in Young Athletes
JF  - Journal of sports science & medicine
N2  - The purpose of this study was to examine the acute effects of short-term Achilles tendon vibration on plantar flexor torque, twitch contractile properties as well as muscle and cortical activity in young athletes. Eleven female elite soccer players aged 15.6 +/- 0.5 years participated in this study. Three different conditions were applied in randomized order: Achilles tendon vibration (80 Hz) for 30 and 300 s, and a passive control condition (300 s). Tests at baseline and following conditions included the assessment of peak plantar flexor torque during maximum voluntary contraction, electrically evoked muscle twitches (e.g., potentiated twitch peak torque [PT]), and electromyographic (EMG) activity of the plantar flexors. Additionally, electroencephalographic (EEG) activity of the primary motor and somatosensory cortex were assessed during a submaximal dynamic concentric-eccentric plantar flexion exercise using an elastic rubber band. Large-sized main effects of condition were found for EEG absolute alpha-1 and beta-1 band power (p <= 0.011; 1.5 <= d <= 2.6). Post-hoc tests indicated that alpha-1 power was significantly lower at 30 and 300 s (p = 0.009; d = 0.8) and beta-1 power significantly lower at 300 s (p < 0.001; d = 0.2) compared to control condition. No significant effect of condition was found for peak plantar flexor torque, electrical evoked muscle twitches, and EMG activity. In conclusion, short-term local Achilles tendon vibration induced lower brain activity (i.e., alpha-1 and beta-1 band power) but did not affect lower limb peak torque, twitch contractile properties, and muscle activity. Lower brain activity following short-term local Achilles tendon vibration may indicate improved cortical function during a submaximal dynamic exercise in female young soccer players.
KW  - Postactivation potentiation
KW  - electromyography
KW  - electroencephalography
KW  - maximum voluntary contraction
KW  - soccer
Y1  - 2019
SN  - 1303-2968
VL  - 18
IS  - 2
SP  - 327
EP  - 336
PB  - Department of Sports Medicine, Medical Faculty of Uludag University
CY  - Bursa
ER  - 
TY  - JOUR
A1  - Prieske, Olaf
A1  - Chaabene, Helmi
A1  - Moran, Jason
A1  - Saeterbakken, Atle Hole
T1  - Adaptations to Advanced Resistance Training Strategies in Youth and Adult Athletes
JF  - Frontiers in physiology / Frontiers Research Foundation
KW  - strength training
KW  - sportsmen
KW  - mechanisms
KW  - chronic effects
KW  - acute effects
KW  - applied physiology
Y1  - 2022
U6  - https://doi.org/10.3389/fphys.2022.888118
SN  - 1664-042X
VL  - 13
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Helm, Norman
A1  - Prieske, Olaf
A1  - Mühlbauer, Thomas
A1  - Krüger, Tom
A1  - Retzlaff, Matthias
A1  - Granacher, Urs
T1  - Associations between trunk muscle strength and judo-specific pulling performances in judo athletes
T1  - Assoziationen zwischen der Rumpfkraft und judospezifischen Anriss-Leistungen von Judoka
JF  - Sportverletzung, Sportschaden : Grundlagen, Prävention, Rehabilitation
N2  - Background:
Good trunk stability is an important prerequisite for the mobility of the upper and lower limbs during sport-specific movements. Therefore, trunk muscle strength may represent an important performance determinant for judo-specific movements. This study aimed at evaluating statistical correlations between trunk muscle strength and kinetic parameters during judo-specific pulling movements in judo players. 

Method:
Twenty-one male sub-elite judo players aged 22 +/- 4 years with a mean training volume of 15 +/- 4 hours per week participated in this study. Peak isokinetic torque (PIT) of the trunk flexors (PITFlex), extensors (PITEx) and rotators (PITRot) was tested using an isokinetic dynamometer (IsoMed 2000). In addition, two kinetic parameters (mechanical work [W], maximal force [F-max]) were analysed using the judo-specific measurement and information system JERGo (c). For this purpose, athletes were asked to do their judo-specific pulling movements while standing and with a dynamic change of position (i.e. Morote-seoi-nage). 

Results:
Regarding pulling movements while standing, significant correlations (0.62 <= r(P) <= 0.72) were found between isokinetic tests (PITFlex, PITEx, PITRot) and mechanical work during judo-specific movement. Further, significant correlations (0.59 <= r(P) <= 0.65) were detected between isokinetic tests (PITEx, PITRot) and judo-specific pulling movements (Fmax). Regarding pulling movements with a change of position, significant correlations (0.47 <= r(P) <= 0.88) were observed between isokinetics (PITFlex, PITEx, PITRot) and the kinetic pulling parameters (W, Fmax), irrespective of the examined arm. No significant differences in magnitude of correlation coefficients were found between PIT of the trunk flexors, extensors, and rotators and judo-specific movements. Further, the regression analysis indicated that PIT of the trunk extensors is the single best predictor for mechanical work during pulling movements while standing (46.9 %). Trunk rotator PIT is the single best predictor for mechanical work during pulling movements with a change of position (69.4 %).

Conclusions:
Findings from this study indicate that trunk muscle strength, particularly trunk rotator PIT is associated with kinetic pulling variables during pulling movements with a change of position. This implies that the development of trunk rotator strength could have an impact on pulling movements with a change of position (i.e. Morote-seoi-nage) in judo athletes.
N2  - Hintergrund:
Eine gut ausgeprägte Rumpfstabilität ist eine wichtige Voraussetzung für die Mobilität der oberen und unteren Extremitäten während des sportlichen Bewegungsvollzugs. Vor diesem Hintergrund könnte die Rumpfkraft ein leistungsdeterminierender Faktor bei der Ausführung judospezifischer Bewegungen darstellen. Das Ziel der vorliegenden Studie war es, statistische Zusammenhänge zwischen der Rumpfkraft und kinetischen Parametern bei Anriss-Bewegungen von Judoka zu untersuchen.

Methode:
An der Untersuchung nahmen 21 leistungsorientierte Judoka mit einem mittleren Alter von 22 ± 4 Jahre und einem Trainingsumfang von 15 ± 4 Stunden pro Woche teil. Das maximale isokinetische Drehmoment (PIT) der Rumpfflexoren (PITFlex), -extensoren (PITEx) und -rotatoren (PITRot) wurde unter Verwendung eines isokinetischen Dynamometers (IsoMed 2000) erfasst. Zusätzlich wurden kinetische Parameter (mechanische Arbeit [W], dynamisch-realisierte Maximalkraft [Fmax]) bei Anriss-Bewegung im Stand und bei Anriss- mit Eindrehbewegung (d. h. Morote-seoi-nage) mithilfe eines judospezifischen Mess- und Informationssystems (JERGo©) erhoben.

Ergebnisse:
Die statistische Analyse zeigte signifikante Korrelationen (0,62 ≤ r P ≤ 0,72) zwischen den maximalen isokinetischen Drehmomenten (PITFlex, PITEx, PITRot) und der Anriss-Bewegung im Stand (W). Zudem konnten signifikante Zusammenhänge (0,59 ≤ r P ≤ 0,65) zwischen den isokinetischen Tests (PITEx, PITRot) und Fmax auf der Hubarmseite bei der Anriss-Bewegung im Stand gefunden werden. Für die Anriss- mit Eindrehbewegung ergaben sich signifikante Korrelationen (0,47 ≤ r P ≤ 0,88) zwischen den isokinetischen Tests (PITFlex, PITEx, PITRot) und Leistungskennwerten der judospezifischen Bewegung (W und Fmax), unabhängig von der untersuchten Armseite. Es wurden vergleichbare Korrelationskoeffizienten zwischen PIT der Rumpfflexoren, -extensoren und -rotatoren und judospezifischen Leistungskennwerten festgestellt. Weiterhin identifizierte die Regressionsanalyse den Kennwert PIT bei Rumpfextension als besten Prädiktor für die mechanische Arbeit bei Anriss-Bewegung im Stand (46,9 %). Bei der Anriss- mit Eindrehbewegung konnte PIT der Rumpfrotatoren auf die Hubarmseite als bester Prädiktor für die mechanische Arbeit (69,4 %) ermittelt werden.

Schlussfolgerung: 
Die Ergebnisse zeigen, dass die Rumpfkraft, insbesondere bei der Rumpfrotationsbewegung, mit Variablen der judospezifischen Leistungskennwerte bei der Anriss- mit Eindrehbewegung assoziiert ist. Dies impliziert, dass vor allem durch rumpfrotationskräftigende Übungen Einfluss auf die Anriss- mit Eindrehbewegung (d. h. Morote-seoi-nage) genommen werden könnte.
KW  - combat sport
KW  - athletic performance
KW  - Morote-seoi-nage
KW  - Kampfsport
KW  - sportliche Leistung
Y1  - 2020
U6  - https://doi.org/10.1055/a-0677-9608
SN  - 0932-0555
SN  - 1439-1236
VL  - 34
IS  - 1
SP  - 18
EP  - 27
PB  - Thieme
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - El-Ashker, Said
A1  - Chaabene, Helmi
A1  - Negra, Yassine
A1  - Prieske, Olaf
A1  - Granacher, Urs
T1  - Cardio-Respiratory Endurance Responses Following a Simulated 3 x 3 Minutes Amateur Boxing Contest in Elite Level Boxers
JF  - Sports
N2  - This study aimed at examining physiological responses (i.e., oxygen uptake [VO2] and heart rate [HR]) to a semi-contact 3 x 3-min format, amateur boxing combat simulation in elite level male boxers. Eleven boxers aged 21.4 +/- 2.1 years (body height 173.4 +/- 3.7, body mass 74.9 +/- 8.6 kg, body fat 12.1 +/- 1.9, training experience 5.7 +/- 1.3 years) volunteered to participate in this study. They performed a maximal graded aerobic test on a motor-driven treadmill to determine maximum oxygen uptake (VO2max), oxygen uptake (VO2AT) and heart rate (HRAT) at the anaerobic threshold, and maximal heart rate (HRmax). Additionally, VO2 and peak HR (HRpeak) were recorded following each boxing round. Results showed no significant differences between VO2max values derived from the treadmill running test and VO2 outcomes of the simulated boxing contest (p > 0.05, d = 0.02 to 0.39). However, HRmax and HRpeak recorded from the treadmill running test and the simulated amateur boxing contest, respectively, displayed significant differences regardless of the boxing round (p < 0.01, d = 1.60 to 3.00). In terms of VO2 outcomes during the simulated contest, no significant between-round differences were observed (p = 0.19, d = 0.17 to 0.73). Irrespective of the boxing round, the recorded VO2 was >90% of the VO2max. Likewise, HRpeak observed across the three boxing rounds were >= 90% of the HRmax. In summary, the simulated 3 x 3-min amateur boxing contest is highly demanding from a physiological standpoint. Thus, coaches are advised to systematically monitor internal training load for instance through rating of perceived exertion to optimize training-related adaptations and to prevent boxers from overreaching and/or overtraining.
KW  - aerobic metabolism
KW  - physiological strain
KW  - striking combat sports
KW  - elite athletes
Y1  - 2018
U6  - https://doi.org/10.3390/sports6040119
SN  - 2075-4663
VL  - 6
IS  - 4
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Chaabene, Helmi
A1  - Prieske, Olaf
A1  - Negra, Yassine
A1  - Granacher, Urs
T1  - Change of direction speed
BT  - toward a strength training approach with accentuated eccentric muscle actions
JF  - Sports medicine
N2  - There is growing evidence that eccentric strength training appears to have benefits over traditional strength training (i.e., strength training with combined concentric and eccentric muscle actions) from muscular, neuromuscular, tendinous, and metabolic perspectives. Eccentric muscle strength is particularly needed to decelerate and stabilize the body during the braking phase of a jump exercise or during rapid changes of direction (CoD) tasks. However, surprisingly little research has been conducted to elucidate the effects of eccentric strength training or strength training with accentuated eccentric muscle actions on CoD speed performance. In this current opinion article, we present findings from cross-sectional studies on the relationship between measures of eccentric muscle strength and CoD speed performance. In addition, we summarize the few available studies on the effects of strength training with accentuated eccentric muscle actions on CoD speed performance in athletic populations. Finally, we propose strength training with accentuated eccentric muscle actions as a promising element in strength and conditioning programs of sports with high CoD speed demands. Our findings from five cross-sectional studies revealed statistically significant moderate-to large-sized correlations (r = 0.45-0.89) between measures of eccentric muscle strength and CoD speed performance in athletic populations. The identified three intervention studies were of limited methodological quality and reported small-to large-sized effects (d = 0.46-1.31) of strength training with accentuated eccentric muscle actions on CoD speed performance in athletes. With reference to the available but preliminary literature and from a performance-related point of view, we recommend strength and conditioning coaches to include strength training with accentuated eccentric muscle actions in training routines of sports with high CoD speed demands (e.g., soccer, handball, basketball, hockey) to enhance sport-specific performance. Future comparative studies are needed to deepen our knowledge of the effects of strength training with accentuated eccentric muscle actions on CoD speed performance in athletes.
Y1  - 2018
U6  - https://doi.org/10.1007/s40279-018-0907-3
SN  - 0112-1642
SN  - 1179-2035
VL  - 48
IS  - 8
SP  - 1773
EP  - 1779
PB  - Springer
CY  - Northcote
ER  - 
TY  - JOUR
A1  - Prieske, Olaf
A1  - Demps, Marie
A1  - Lesinski, Melanie
A1  - Granacher, Urs
T1  - Combined Effects of Fatigue and Surface Instability on Jump Biomechanics in Elite Athletes
JF  - International journal of sports medicine
N2  - The present study aimed to examine the effects of fatigue and surface instability on kinetic and kinematic jump performance measures. Ten female and 10 male elite volleyball players (18 +/- 2 years) performed repetitive vertical double-leg box jumps until failure. Pre and post fatigue, jump height/performance index, ground reaction force and knee flexion/valgus angles were assessed during drop and countermovement jumps on stable and unstable surfaces. Fatigue, surface condition, and sex resulted in significantly lower drop jump performance and ground reaction force (p0.031, 1.1d3.5). Additionally, drop jump knee flexion angles were significantly lower following fatigue (p=0.006, d=1.5). A significant fatiguexsurfacexsex interaction (p=0.020, d=1.2) revealed fatigue-related decrements in drop jump peak knee flexion angles under unstable conditions and in men only. Knee valgus angles were higher on unstable compared to stable surfaces during drop jumps and in females compared to males during drop and countermovement jumps (p0.054, 1.0d1.1). Significant surfacexsex interactions during countermovement jumps (p=0.002, d=1.9) indicated that knee valgus angles at onset of ground contact were significantly lower on unstable compared to stable surfaces in males but higher in females. Our findings revealed that fatigue and surface instability resulted in sex-specific knee motion strategies during jumping in elite volleyball players.
KW  - stretch-shortening cycle
KW  - knee joint angle
KW  - exhaustion
KW  - injury risk
KW  - gender
Y1  - 2017
U6  - https://doi.org/10.1055/s-0043-111894
SN  - 0172-4622
SN  - 1439-3964
VL  - 38
SP  - 781
EP  - 790
PB  - Thieme
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Khudair, Mohammed
A1  - Marcuzzi, Anna
A1  - Ng, Kwok
A1  - Tempest, Gavin Daniel
A1  - Bartoš, František
A1  - Peric, Ratko
A1  - Maier, Maximilian
A1  - Beccia, Flavia
A1  - Boccia, Stefania
A1  - Brandes, Mirko
A1  - Cardon, Greet
A1  - Carlin, Angela
A1  - Castagna, Carolina
A1  - Chaabene, Helmi
A1  - Chalkley, Anna
A1  - Ciaccioni, Simone
A1  - Cieślińska-Świder, Joanna
A1  - Čingienė, Vilma
A1  - Cortis, Cristina
A1  - Corvino, Chiara
A1  - de Geus, Eco J. C.
A1  - Di Baldassarre, Angela
A1  - Di Credico, Andrea
A1  - Drid, Patrik
A1  - Tarazaga, Rosa Ma Fernández
A1  - Gallè, Francesca
A1  - Sánchez, Esther Garcia
A1  - Gebremariam, Mekdes
A1  - Ghinassi, Barbara
A1  - Goudas, Marios
A1  - Hayes, Grainne
A1  - Honorio, Samuel
A1  - Izzicupo, Pascal
A1  - Jahre, Henriette
A1  - Jelsma, Judith
A1  - Juric, Petra
A1  - Kolovelonis, Athanasios
A1  - Kongsvold, Atle
A1  - Kouidi, Evangelia
A1  - Mansergh, Fiona
A1  - Masanovic, Bojan
A1  - Mekonnen, Teferi
A1  - Mork, Paul Jarle
A1  - Murphy, Marie
A1  - O'Hara, Kelly
A1  - Torun, Ayse Ozbil
A1  - Palumbo, Federico
A1  - Popovic, Stevo
A1  - Prieske, Olaf
A1  - Puharic, Zrinka
A1  - Ribeiro, José Carlos
A1  - Rumbold, Penny Louise Sheena
A1  - Sandu, Petru
A1  - Soric, Maroje
A1  - Stavnsbo, Mette
A1  - Syrmpas, Ioannis
A1  - van der Ploeg, Hidde P.
A1  - Van Hoye, Aurélie
A1  - Vilela, Sofia
A1  - Woods, Catherine
A1  - Wunsch, Kathrin
A1  - Caprinica, Laura
A1  - MacDonncha, Ciaran
A1  - Ling, Fiona Chun Man
T1  - DE-PASS Best Evidence Statement (BESt): modifiable determinants of physical activity and sedentary behaviour in children and adolescents aged 5-19 years-a protocol for systematic review and meta-analysis
JF  - BMJ open
N2  - Introduction Physical activity among children and adolescents remains insufficient, despite the substantial efforts made by researchers and policymakers. Identifying and furthering our understanding of potential modifiable determinants of physical activity behaviour (PAB) and sedentary behaviour (SB) is crucial for the development of interventions that promote a shift from SB to PAB. The current protocol details the process through which a series of systematic literature reviews and meta-analyses (MAs) will be conducted to produce a best-evidence statement (BESt) and inform policymakers. The overall aim is to identify modifiable determinants that are associated with changes in PAB and SB in children and adolescents (aged 5-19 years) and to quantify their effect on, or association with, PAB/SB. Methods and analysis A search will be performed in MEDLINE, SportDiscus, Web of Science, PsychINFO and Cochrane Central Register of Controlled Trials. Randomised controlled trials (RCTs) and controlled trials (CTs) that investigate the effect of interventions on PAB/SB and longitudinal studies that investigate the associations between modifiable determinants and PAB/SB at multiple time points will be sought. Risk of bias assessments will be performed using adapted versions of Cochrane's RoB V.2.0 and ROBINS-I tools for RCTs and CTs, respectively, and an adapted version of the National Institute of Health's tool for longitudinal studies. Data will be synthesised narratively and, where possible, MAs will be performed using frequentist and Bayesian statistics. Modifiable determinants will be discussed considering the settings in which they were investigated and the PAB/SB measurement methods used. Ethics and dissemination No ethical approval is needed as no primary data will be collected. The findings will be disseminated in peer-reviewed publications and academic conferences where possible. The BESt will also be shared with policy makers within the DE-PASS consortium in the first instance. Systematic review registration CRD42021282874.
KW  - public health
KW  - health policy
KW  - community child health
Y1  - 2022
U6  - https://doi.org/10.1136/bmjopen-2021-059202
SN  - 2044-6055
VL  - 12
IS  - 9
PB  - BMJ Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Chaabene, Helmi
A1  - Markov, Adrian
A1  - Prieske, Olaf
A1  - Moran, Jason
A1  - Behrens, Martin
A1  - Negra, Yassine
A1  - Ramirez-Campillo, Rodrigo
A1  - Koch, Ulrike
A1  - Mkaouer, Bessem
T1  - Effect of flywheel versus traditional resistance training on change of direction performance in male athletes
BT  - a systematic review with meta-analysis
JF  - International journal of environmental research and public health : IJERPH
N2  - Objective: 
This study aimed to systematically review and meta-analyze the effect of flywheel resistance training (FRT) versus traditional resistance training (TRT) on change of direction (CoD) performance in male athletes. 

Methods: 
Five databases were screened up to December 2021. 

Results: 
Seven studies were included. The results indicated a significantly larger effect of FRT compared with TRT (standardized mean difference [SMD] = 0.64). A within-group comparison indicated a significant large effect of FRT on CoD performance (SMD = 1.63). For TRT, a significant moderate effect was observed (SMD = 0.62). FRT of <= 2 sessions/week resulted in a significant large effect (SMD = 1.33), whereas no significant effect was noted for >2 sessions/week. Additionally, a significant large effect of <= 12 FRT sessions (SMD = 1.83) was observed, with no effect of >12 sessions. Regarding TRT, no significant effects of any of the training factors were detected (p > 0.05). 

Conclusions: 
FRT appears to be more effective than TRT in improving CoD performance in male athletes. Independently computed single training factor analyses for FRT indicated that <= 2 sessions/week resulted in a larger effect on CoD performance than >2 sessions/week. Additionally, a total of <= 12 FRT sessions induced a larger effect than >12 training sessions. Practitioners in sports, in which accelerative and decelerative actions occur in quick succession to change direction, should regularly implement FRT.
KW  - human physical conditioning
KW  - eccentric training
KW  - strength training
KW  - athletes
KW  - sports
KW  - muscle strength
Y1  - 2022
U6  - https://doi.org/10.3390/ijerph19127061
SN  - 1661-7827
SN  - 1660-4601
VL  - 19
IS  - 12
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Kuemmel, Jakob
A1  - Bergmann, Julian
A1  - Prieske, Olaf
A1  - Kramer, Andreas
A1  - Granacher, Urs
A1  - Gruber, Markus
T1  - Effects of conditioning hops on drop jump and sprint performance: a randomized crossover pilot study in elite athletes
JF  - BMC sports science, medicine & rehabilitation
N2  - Background: It has previously been shown that conditioning activities consisting of repetitive hops have the potential to induce better drop jump (DJ) performance in recreationally active individuals. In the present pilot study, we investigated whether repetitive conditioning hops can also increase reactive jump and sprint performance in sprint-trained elite athletes competing at an international level. Methods: Jump and sprint performances of 5 athletes were randomly assessed under 2 conditions. The control condition (CON) comprised 8 DJs and 4 trials of 30-m sprints. The intervention condition (HOP) consisted of 10 maximal repetitive two-legged hops that were conducted 10 s prior to each single DJ and sprint trial. DJ performance was analyzed using a one-dimensional ground reaction force plate. Step length (SL), contact time (CT), and sprint time (ST) during the 30-m sprints were recorded using an opto-electronic measurement system. Results: Following the conditioning activity, DJ height and external DJ peak power were both significantly increased by 11 % compared to the control condition. All other variables did not show any significant differences between HOP and CON. Conclusions: In the present pilot study, we were able to demonstrate large improvements in DJ performance even in sprint-trained elite athletes following a conditioning activity consisting of maximal two-legged repetitive hops. This strengthens the hypothesis that plyometric conditioning exercises can induce performance enhancements in elite athletes that are even greater than those observed in recreationally active athletes.. In addition, it appears that the transfer of these effects to other stretch-shortening cycle activities is limited, as we did not observe any changes in sprint performance following the plyometric conditioning activity.
KW  - Post-activation potentiation
KW  - Performance gains
KW  - Reactive movement
KW  - Plyometric exercise
Y1  - 2016
U6  - https://doi.org/10.1186/s13102-016-0027-z
SN  - 2052-1847
VL  - 8
PB  - BioMed Central
CY  - London
ER  - 
TY  - JOUR
A1  - Granacher, Urs
A1  - Schellbach, Jörg
A1  - Klein, Katja
A1  - Prieske, Olaf
A1  - Baeyens, Jean-Pierre
A1  - Mühlbauer, Thomas
T1  - Effects of core strength training using stable versus unstable surfaces on physical fitness in adolescents
BT  - a randomized controlled trial
JF  - BMC sports science, medicine & rehabilitation
N2  - Background
It has been demonstrated that core strength training is an effective means to enhance trunk muscle strength (TMS) and proxies of physical fitness in youth. Of note, cross-sectional studies revealed that the inclusion of unstable elements in core strengthening exercises produced increases in trunk muscle activity and thus provide potential extra training stimuli for performance enhancement. Thus, utilizing unstable surfaces during core strength training may even produce larger performance gains. However, the effects of core strength training using unstable surfaces are unresolved in youth. This randomized controlled study specifically investigated the effects of core strength training performed on stable surfaces (CSTS) compared to unstable surfaces (CSTU) on physical fitness in school-aged children.

Methods
Twenty-seven (14 girls, 13 boys) healthy subjects (mean age: 14 ± 1 years, age range: 13–15 years) were randomly assigned to a CSTS (n = 13) or a CSTU (n = 14) group. Both training programs lasted 6 weeks (2 sessions/week) and included frontal, dorsal, and lateral core exercises. During CSTU, these exercises were conducted on unstable surfaces (e.g., TOGU© DYNAIR CUSSIONS, THERA-BAND© STABILITY TRAINER).

Results
Significant main effects of Time (pre vs. post) were observed for the TMS tests (8-22%, f = 0.47-0.76), the jumping sideways test (4-5%, f = 1.07), and the Y balance test (2-3%, f = 0.46-0.49). Trends towards significance were found for the standing long jump test (1-3%, f = 0.39) and the stand-and-reach test (0-2%, f = 0.39). We could not detect any significant main effects of Group. Significant Time x Group interactions were detected for the stand-and-reach test in favour of the CSTU group (2%, f = 0.54).

Conclusions
Core strength training resulted in significant increases in proxies of physical fitness in adolescents. However, CSTU as compared to CSTS had only limited additional effects (i.e., stand-and-reach test). Consequently, if the goal of training is to enhance physical fitness, then CSTU has limited advantages over CSTS.
KW  - Resistance training
KW  - Trunk muscle strength
KW  - Physical fitness
Y1  - 2014
U6  - https://doi.org/10.1186/2052-1847-6-40
SN  - 2052-1847
VL  - 6
PB  - BioMed Central
CY  - London
ER  - 
TY  - JOUR
A1  - Lesinski, Melanie
A1  - Prieske, Olaf
A1  - Borde, Ron
A1  - Beurskens, Rainer
A1  - Granacher, Urs
T1  - Effects of Different Footwear Properties and Surface Instability on Neuromuscular Activity and Kinematics During Jumping
JF  - Journal of strength and conditioning research : the research journal of the NSCA
N2  - The purpose of this study was to examine sex-specific effects of different footwear properties vs. barefoot condition during the performance of drop jumps (DJs) on stable and unstable surfaces on measures of jump performance, electromyographic (EMG) activity, and knee joint kinematics. Drop jump performance, EMG activity of lower-extremity muscles, as well as sagittal and frontal knee joint kinematics were tested in 28 healthy male (n = 14) and female (n = 14) physically active sports science students (23 6 2 years) during the performance of DJs on stable and unstable surfaces using different footwear properties (elastic vs. minimal shoes) vs. barefoot condition. Analysis revealed a significantly lower jump height and performance index (Delta 7-12%; p < 0.001; 2.22 <= d = 2.90) during DJs on unstable compared with stable surfaces. This was accompanied by lower thigh/shank muscle activities (Delta 11-28%; p < 0.05; 0.99 <= d = 2.16) and knee flexion angles (Delta 5-8%; p < 0.05; 1.02 <= d = 2.09). Furthermore, knee valgus angles during DJs were significantly lower when wearing shoes compared with barefoot condition (Delta 22-32%; p < 0.01; 1.38 <= d = 3.31). Sex-specific analyses indicated higher knee flexion angles in females compared with males during DJs, irrespective of the examined surface and footwear conditions (Delta 29%; p < 0.05; d = 0.92). Finally, hardly any significant footwear-surface interactions were detected. Our findings revealed that surface instability had an impact on DJ performance, thigh/shank muscle activity, and knee joint kinematics. In addition, the single factors "footwear" and "sex" modulated knee joint kinematics during DJs. However, hardly any significant interaction effects were found. Thus, additional footwear-related effects can be neglected when performing DJs during training on different surfaces.
KW  - shoe
KW  - drop jump
KW  - EMG
KW  - knee
KW  - biomechanics
Y1  - 2018
U6  - https://doi.org/10.1519/JSC.0000000000002556
SN  - 1064-8011
SN  - 1533-4287
VL  - 32
IS  - 11
SP  - 3246
EP  - 3257
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Lesinski, Melanie
A1  - Prieske, Olaf
A1  - Beurskens, Rainer
A1  - Behm, David George
A1  - Granacher, Urs
T1  - Effects of drop height and surface instability on neuromuscular activation during drop jumps
JF  - Scandinavian journal of medicine & science in sports
N2  - The purpose of this study was to examine whether drop height-induced changes in leg muscle activity during drop jumps (DJ) are additionally modulated by surface condition. Twenty-four healthy participants (23.7 +/- 1.8years) performed DJs on a force plate on stable, unstable, and highly unstable surfaces using different drop heights (i.e., 20cm, 40cm, 60cm). Electromyographic (EMG) activity of soleus (SOL), gastrocnemius (GM), tibialis anterior (TA) muscles and coactivation of TA/SOL and TA/GM were analyzed for time intervals 100ms prior to ground contact (preactivation) and 30-60ms after ground contact [short latency response (SLR)]. Increasing drop heights resulted in progressively increased SOL and GM activity during preactivation and SLR (P<0.01; 1.01 d 5.34) while TA/SOL coactivation decreased (P<0.05; 0.51 d 3.01). Increasing surface instability produced decreased activities during preactivation (GM) and SLR (GM, SOL) (P<0.05; 1.36 d 4.30). Coactivation increased during SLR (P<0.05; 1.50 d 2.58). A significant drop heightxsurface interaction was observed for SOL during SLR. Lower SOL activity was found on unstable compared to stable surfaces for drop heights 40cm (P<0.05; 1.25 d 2.12). Findings revealed that instability-related changes in activity of selected leg muscles are minimally affected by drop height.
KW  - Stretch-shortening cycle
KW  - EMG
KW  - preactivation
KW  - short latency response
Y1  - 2017
U6  - https://doi.org/10.1111/sms.12732
SN  - 0905-7188
SN  - 1600-0838
VL  - 27
SP  - 1090
EP  - 1098
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Prieske, Olaf
A1  - Chaabene, Helmi
A1  - Puta, Christian
A1  - Behm, David George
A1  - Büsch, Dirk
A1  - Granacher, Urs
T1  - Effects of Drop Height on Jump Performance in Male and Female Elite Adolescent Handball Players
JF  - International journal of sports physiology and performance
N2  - Purpose: To examine the effects of drop height on drop-jump (DJ) performance and on associations between DJ and horizontal-jump/sprint performances in adolescent athletes. Methods: Male (n = 119, 2.5 [0.6] y post-peak-height velocity) and female (n = 120, 2.5 [0.5] y post-peak-height velocity) adolescent handball players (national level) performed DJs in randomized order using 3 drop heights (20, 35, and 50 cm). DJ performance (jump height, reactive strength index [RSI]) was analyzed using the Optojump Next system. In addition, correlations were computed between DJ height and RSI with standing-long-jump and 20-m linear-sprint performances. Results: Statistical analyses revealed medium-size main effects of drop height for DJ height and RSI (P <.001, 0.63 <= d <= 0.71). Post hoc tests indicated larger DJ heights from 20 to 35 and 35 to 50 cm (P <=.031, 0.33 <= d <= 0.71) and better RSI from 20- to 35-cm drop height (P <.001, d = 0.77). No significant difference was found for RSI between 35- and 50-cm drop height. Irrespective of drop height, associations of DJ height and RSI were small with 5-m-split time (-.27 <= r <=.05), medium with 10-m-split time (-.44 <= r <=.14), and medium to large with 20-m sprint time and standing-long-jump distance (-.57 <= r <=.22). Conclusions: The present findings indicate that, irrespective of sex, 35-cm drop heights are best suited to induce rapid and powerful DJ performance (ie, RSI) during reactive strength training in elite adolescent handball players. Moreover, training-related gains in DJ performance may at least partly translate to gains in horizontal jump and longer sprint distances (ie, >= 20-m) and/or vice versa in male and female elite adolescent athletes, irrespective of drop height.
KW  - stretch-shortening cycle
KW  - plyometric training
KW  - strength training
KW  - tendon stiffness
KW  - young athletes
Y1  - 2019
U6  - https://doi.org/10.1123/ijspp.2018-0482
SN  - 1555-0265
SN  - 1555-0273
VL  - 14
IS  - 5
SP  - 674
EP  - 680
PB  - Human Kinetics Publ.
CY  - Champaign
ER  - 
TY  - JOUR
A1  - Lesinski, Melanie
A1  - Prieske, Olaf
A1  - Beurskens, Rainer
A1  - Behm, David George
A1  - Granacher, Urs
T1  - Effects of Drop-height and Surface Instability on Jump Performance and Knee Kinematics
JF  - International journal of sports medicine
N2  - The purpose of this study was to examine the combined effects of drop-height and surface condition on drop jump (DJ) performance and knee joint kinematics. DJ performance, sagittal and frontal plane knee joint kinematics were measured in jump experienced young male and female adults during DJs on stable, unstable and highly unstable surfaces using different drop-heights (20, 40, 60 cm). Findings revealed impaired DJ performance (Δ5–16%; p<0.05; 1.43≤d≤2.82), reduced knee valgus motion (Δ33–52%; p<0.001; 2.70≤d≤3.59), and larger maximum knee flexion angles (Δ13–19%; p<0.01; 1.74≤d≤1.75) when using higher (60 cm) compared to lower drop-heights (≤40 cm). Further, lower knee flexion angles and velocity were found (Δ8-16%; p<0.01; 1.49≤d≤2.38) with increasing surface instability. When performing DJs from high (60 cm) compared to moderate drop-heights (40 cm) on highly unstable surfaces, higher knee flexion velocity and maximum knee valgus angles were found (Δ15–19%; p<0.01; 1.50≤d≤1.53). No significant main and/or interaction effects were observed for the factor sex. In conclusion, knee motion strategies were modified by the factors ‘drop-height’ and/or ‘surface instability’. The combination of high drop-heights (>40 cm) together with highly unstable surfaces should be used cautiously during plyometrics because this may increase the risk of injury due to higher knee valgus stress.
KW  - drop jump
KW  - knee flexion angle
KW  - knee valgus angle
KW  - knee valgus motion
Y1  - 2017
U6  - https://doi.org/10.1055/s-0043-117610
SN  - 0172-4622
SN  - 1439-3964
VL  - 39
IS  - 1
SP  - 50
EP  - 57
PB  - Thieme
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Thiele, Dirk
A1  - Prieske, Olaf
A1  - Lesinski, Melanie
A1  - Granacher, Urs
T1  - Effects of Equal Volume Heavy-Resistance Strength Training Versus Strength Endurance Training on Physical Fitness and Sport-Specific Performance in Young Elite Female Rowers
JF  - Frontiers in Physiology
N2  - Strength training is an important means for performance development in young rowers. The purpose of this study was to examine the effects of a 9-week equal volume heavy-resistance strength training (HRST) versus strength endurance training (SET) in addition to regular rowing training on primary (e.g., maximal strength/power) and secondary outcomes (e.g., balance) in young rowers. Twenty-six female elite adolescent rowers were assigned to an HRST (n = 12; age: 13.2 ± 0.5 yrs; maturity-offset: +2.0 ± 0.5 yrs) or a SET group (n = 14; age: 13.1 ± 0.5 yrs; maturity-offset: +2.1 ± 0.5 yrs). HRST and SET comprised lower- (i.e., leg press/knee flexion/extension), upper-limbs (i.e., bench press/pull; lat-pull down), and complex exercises (i.e., rowing ergometer). HRST performed four sets with 12 repetitions per set at an intensity of 75–95% of the one-repetition maximum (1-RM). SET conducted four sets with 30 repetitions per set at 50–60% of the 1-RM. Training volume was matched for overall repetitions × intensity × training per week. Pre-post training, tests were performed for the assessment of primary [i.e., maximal strength (e.g., bench pull/knee flexion/extension 1-RM/isometric handgrip test), muscle power (e.g., medicine-ball push test, triple hop, drop jump, and countermovement jump), anaerobic endurance (400-m run), sport-specific performance (700-m rowing ergometer trial)] and secondary outcomes [dynamic balance (Y-balance test), change-of-direction (CoD) speed (multistage shuttle-run test)]. Adherence rate was >87% and one athlete of each group dropped out. Overall, 24 athletes completed the study and no test or training-related injuries occurred. Significant group × time interactions were observed for maximal strength, muscle power, anaerobic endurance, CoD speed, and sport-specific performance (p ≤ 0.05; 0.45 ≤ d ≤ 1.11). Post hoc analyses indicated larger gains in maximal strength and muscle power following HRST (p ≤ 0.05; 1.81 ≤ d ≤ 3.58) compared with SET (p ≤ 0.05; 1.04 ≤ d ≤ 2.30). Furthermore, SET (p ≤ 0.01; d = 2.08) resulted in larger gains in sport-specific performance compared with HRST (p < 0.05; d = 1.3). Only HRST produced significant pre-post improvements for anaerobic endurance and CoD speed (p ≤ 0.05; 1.84 ≤ d ≤ 4.76). In conclusion, HRST in addition to regular rowing training was more effective than SET to improve selected measures of physical fitness (i.e., maximal strength, muscle power, anaerobic endurance, and CoD speed) and SET was more effective than HRST to enhance sport-specific performance gains in female elite young rowers.
KW  - concurrent training
KW  - plyometric training
KW  - on-water performance
KW  - race time
KW  - oarsmen
Y1  - 2020
U6  - https://doi.org/10.3389/fphys.2020.00888
SN  - 1664-042X
VL  - 11
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Lesinski, Melanie
A1  - Prieske, Olaf
A1  - Demps, Marie
A1  - Granacher, Urs
T1  - Effects of fatigue and surface instability on neuromuscular performance during jumping
JF  - Der Schmerz : Organ der Deutschen Gesellschaft zum Studium des Schmerzes, der Österreichischen Schmerzgesellschaft und der Deutschen Interdisziplinären Vereinigung für Schmerztherapie
N2  - It has previously been shown that fatigue and unstable surfaces affect jump performance. However, the combination thereof is unresolved. Thus, the purpose of this study was to examine the effects of fatigue and surface instability on jump performance and leg muscle activity. Twenty elite volleyball players (18 +/- 2 years) performed repetitive vertical double-leg box jumps until failure. Before and after a fatigue protocol, jump performance (i.e., jump height) and electromyographic activity of selected lower limb muscles were recorded during drop jumps (DJs) and countermovement jumps (CMJs) on a force plate on stable and unstable surfaces (i.e., balance pad on top of force plate). Jump performance (3-7%; P < 0.05; 1.14 <= d <= 2.82), and muscle activity (2-27%; P < 0.05; 0.59 <= d <= 3.13) were lower following fatigue during DJs and CMJs, and on unstable compared with stable surfaces during DJs only (jump performance: 8%; P < 0.01; d = 1.90; muscle activity: 9-25%; P < 0.05; 1.08 <= d <= 2.54). No statistically significant interactions of fatigue by surface condition were observed. Our findings revealed that fatigue impairs neuromuscular performance during DJs and CMJs in elite volleyball players, whereas surface instability affects neuromuscular DJ performance only. Absent fatigue x surface interactions indicate that fatigue-induced changes in jump performance are similar on stable and unstable surfaces in jump-trained athletes.
KW  - Exhaustion
KW  - stretch-shortening cycle
KW  - jump height
KW  - EMG
KW  - athlete.
Y1  - 2016
U6  - https://doi.org/10.1111/sms.12548
SN  - 0905-7188
SN  - 1600-0838
VL  - 26
SP  - 1140
EP  - 1150
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Prieske, Olaf
A1  - Chaabene, Helmi
A1  - Kullmann, Niclas
A1  - Granacher, Urs
T1  - Effects of Individualized Versus Traditional Power Training on Strength, Power, Jump Performances, and Body Composition in Young Male Nordic Athletes
JF  - International journal of sports physiology and performance
N2  - Purpose:
This study aimed to examine the effects of individualized-load power training (IPT) versus traditional moderate-load power training (TPT) on strength, power, jump performance, and body composition in elite young Nordic athletes.

Methods:
In a randomized crossover design, 10 young male athletes (ski jumpers, Nordic combined athletes) age 17.5 (0.6) years (biological maturity status: +3.5 y postpeak height velocity) who competed on a national or international level performed 5 weeks of IPT (4 x 5 repetitions at 49%-72% 1-repetiton maximum [RM]) and TPT (5 x 5 repetitions at 50%-60% 1-RM) in addition to their regular training. Testing before, between, and after both training blocks comprised the assessment of muscle strength (loaded back squat 3-RM), power (maximal loaded back squat power), jump performance (eg, drop-jump height, reactive strength index), and body composition (eg, skeletal muscle mass).

Results: 
Significant, large-size main effects for time were found for muscle strength (P < .01; g = 2.7), reactive strength index (P = .03; g= 1.6), and drop jump height (P = .02; g= 1.9) irrespective of the training condition (IPT, TPT). No significant time-by-condition interactions were observed. For measures of body composition, no significant main effects of condition and time or time-by-condition interactions were found. 

Conclusions:
Our findings demonstrate that short-term IPT and TPT at moderate loads in addition to regular training were equally effective in improving measures of muscle strength (loaded back squat 3-RM) and vertical jump performance (reactive strength index, drop jump, and height) in young Nordic athletes.
KW  - ballistic training
KW  - optimal load
KW  - monitoring
KW  - progression
KW  - ski jumping
Y1  - 2022
U6  - https://doi.org/10.1123/ijspp.2021-0074
SN  - 1555-0265
SN  - 1555-0273
VL  - 17
IS  - 4
SP  - 541
EP  - 548
PB  - Human Kinetics Publ.
CY  - Champaign
ER  - 
TY  - JOUR
A1  - El-Ashker, Said
A1  - Chaabene, Helmi
A1  - Prieske, Olaf
A1  - Abdelkafy, Ashraf
A1  - Ahmed, Mohamed A.
A1  - Muaidi, Qassim I.
A1  - Granacher, Urs
T1  - Effects of Neuromuscular Fatigue on Eccentric Strength and Electromechanical Delay of the Knee Flexors
BT  - The Role of Training Status
JF  - Frontiers in Physiology
N2  - Purpose: To examine the effects of fatiguing isometric contractions on maximal eccentric strength and electromechanical delay (EMD) of the knee flexors in healthy young adults of different training status.

Methods: Seventy-five male participants (27.7 ± 5.0 years) were enrolled in this study and allocated to three experimental groups according to their training status: athletes (ATH, n = 25), physically active adults (ACT, n = 25), and sedentary participants (SED, n = 25). The fatigue protocol comprised intermittent isometric knee flexions (6-s contraction, 4-s rest) at 60% of the maximum voluntary contraction until failure. Pre- and post-fatigue, maximal eccentric knee flexor strength and EMDs of the biceps femoris, semimembranosus, and semitendinosus muscles were assessed during maximal eccentric knee flexor actions at 60, 180, and 300°/s angular velocity. An analysis of covariance was computed with baseline (unfatigued) data included as a covariate.

Results: Significant and large-sized main effects of group (p ≤ 0.017, 0.87 ≤ d ≤ 3.69) and/or angular velocity (p < 0.001, d = 1.81) were observed. Post hoc tests indicated that regardless of angular velocity, maximal eccentric knee flexor strength was lower and EMD was longer in SED compared with ATH and ACT (p ≤ 0.025, 0.76 ≤ d ≤ 1.82) and in ACT compared with ATH (p = ≤0.025, 0.76 ≤ d ≤ 1.82). Additionally, EMD at post-test was significantly longer at 300°/s compared with 60 and 180°/s (p < 0.001, 2.95 ≤ d ≤ 4.64) and at 180°/s compared with 60°/s (p < 0.001, d = 2.56), irrespective of training status.

Conclusion: The main outcomes revealed significantly higher maximal eccentric strength and shorter eccentric EMDs of knee flexors in individuals with higher training status (i.e., athletes) following fatiguing exercises. Therefore, higher training status is associated with better neuromuscular functioning (i.e., strength, EMD) of the hamstring muscles in fatigued condition. Future longitudinal studies are needed to substantiate the clinical relevance of these findings.
KW  - muscle activation
KW  - hamstring muscles
KW  - latency
KW  - injury risk
KW  - physical fitness expertise
Y1  - 2019
U6  - https://doi.org/10.3389/fphys.2019.00782
SN  - 1664-042X
VL  - 10
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Prieske, Olaf
A1  - Dalager, Tina
A1  - Herz, Michael
A1  - Hortobagyi, Tibor
A1  - Sjogaard, Gisela
A1  - Sogaard, Karen
A1  - Granacher, Urs
T1  - Effects of Physical Exercise Training in the Workplace on Physical Fitness: A Systematic Review and Meta-analysis
JF  - Sports medicine
N2  - Background There is evidence that physical exercise training (PET) conducted at the workplace is effective in improving physical fitness and thus health. However, there is no current systematic review available that provides high-level evidence regarding the effects of PET on physical fitness in the workforce. Objectives To quantify sex-, age-, and occupation type-specific effects of PET on physical fitness and to characterize dose-response relationships of PET modalities that could maximize gains in physical fitness in the working population. Data Sources A computerized systematic literature search was conducted in the databases PubMed and Cochrane Library (2000-2019) to identify articles related to PET in workers. Study Eligibility Criteria Only randomized controlled trials with a passive control group were included if they investigated the effects of PET programs in workers and tested at least one fitness measure. Study Appraisal and Synthesis Methods Weighted mean standardised mean differences (SMDwm) were calculated using random effects models. A multivariate random effects meta-regression was computed to explain the influence of key training modalities (e.g., training frequency, session duration, intensity) on the effectiveness of PET on measures of physical fitness. Further, subgroup univariate analyses were computed for each training modality. Additionally, methodological quality of the included studies was rated with the help of the Physiotherapy Evidence Database (PEDro) Scale. Results Overall, 3423 workers aged 30-56 years participated in 17 studies (19 articles) that were eligible for inclusion. Methodological quality of the included studies was moderate with a median PEDro score of 6. Our analyses revealed significant, small-sized effects of PET on cardiorespiratory fitness (CRF), muscular endurance, and muscle power (0.29 <= SMDwm <= 0.48). Medium effects were found for CRF and muscular endurance in younger workers (<= 45 years) (SMDwm = 0.71) and white-collar workers (SMDwm = 0.60), respectively. Multivariate random effects meta-regression for CRF revealed that none of the examined training modalities predicted the effects of PET on CRF (R-2 = 0). Independently computed subgroup analyses showed significant PET effects on CRF when conducted for 9-12 weeks (SMDwm = 0.31) and for 17-20 weeks (SMDwm = 0.74). Conclusions PET effects on physical fitness in healthy workers are moderated by age (CRF) and occupation type (muscular endurance). Further, independently computed subgroup analyses indicated that the training period of the PET programs may play an important role in improving CRF in workers.
Y1  - 2019
U6  - https://doi.org/10.1007/s40279-019-01179-6
SN  - 0112-1642
SN  - 1179-2035
VL  - 49
IS  - 12
SP  - 1903
EP  - 1921
PB  - Springer
CY  - Northcote
ER  -