TY - JOUR A1 - Chaabene, Helmi A1 - Negra, Yassine A1 - Moran, Jason A1 - Prieske, Olaf A1 - Sammoud, Senda A1 - Ramirez-Campillo, Rodrigo A1 - Granacher, Urs T1 - Plyometric training improves not only measures of linear speed, power, and change-of-direction speed but also repeated sprint ability in young female handball players JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - This study examined the effects of an 8-week plyometric training (PT) program on components of physical fitness in young female handball players. Twenty-one female adolescent handball players were assigned to an experimental group (EG, n = 12; age = 15.9 +/- 0.2 years) or an active control group (CG, n = 9, age = 15.9 +/- 0.3 years). While EG performed plyometric exercises in replacement of some handball-specific drills, CG maintained the regular training schedule. Baseline and follow-up tests were performed for the assessment of linear speed (i.e., 5-, 10-, and 20-m time), change-of-direction (CoD) speed (i.e., T-test time), muscle power (i.e., countermovement jump [CMJ] height and reactive strength index [RSI]), and repeated sprint ability (RSA) (RSA total time [RSA(total)], RSA best time [RSA(best)], and RSA fatigue index [RSA(FI)]). Data were analyzed using magnitude-based inferences. Within-group analyses for the EG revealed moderate-to-large improvements for the 5-m (effect size [ES] = 0.81 [0.1-1.5]), 10-m sprint time (ES = 0.84 [0.1-1.5]), RSI (ES = 0.75 [0.1-1.4]), RSA(FI) (ES = 0.65 [0.0-1.3]), and T-test time (ES = 1.46 [0.7-2.2]). Trivial-to-small ES was observed for RSA(best) (ES = 0.18 [-0.5 to 0.9]), RSA(total) (ES = 0.45 [-0.2 to 1.1]), 20-m sprint time (ES = 0.56 [-0.1 to 1.2]), and CMJ height (ES = 0.57 [-0.1 to 1.3]). For the CG, within-group analyses showed a moderate performance decline for T-test time (ES = -0.71 [-1.5 to 0.1]), small decreases for 5-m sprint time (ES = -0.46 [-1.2 to 0.3]), and a trivial decline for 10-m (ES = -0.10 [-0.9 to 0.7]) and 20-m sprint times (ES = -0.16 [-0.9 to 0.6]), RSA(total) (ES = 0.0 [-0.8 to 0.8]), and RSA(best) (ES = -0.20 [-0.9 to 0.6]). The control group achieved trivial-to-small improvements for CMJ height (ES = 0.10 [-0.68 to 0.87]) and RSI (ES = 0.30 [-0.5 to 1.1]). In conclusion, a short-term in-season PT program, in replacement of handball-specific drills, is effective in improving measures of physical fitness (i.e., linear/CoD speed, jumping, and RSA) in young female handball players. KW - stretch-shortening cycle KW - physical fitness KW - young athletes Y1 - 2021 U6 - https://doi.org/10.1519/JSC.0000000000003128 SN - 1064-8011 SN - 1533-4287 VL - 35 IS - 8 SP - 2230 EP - 2235 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - GEN A1 - Kibele, Armin A1 - Classen, Claudia A1 - Mühlbauer, Thomas A1 - Granacher, Urs A1 - Behm, David George T1 - Metastability in plyometric training on unstable surfaces BT - a pilot study T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Background In the past, plyometric training (PT) has been predominantly performed on stable surfaces. The purpose of this pilot study was to examine effects of a 7-week lower body PT on stable vs. unstable surfaces. This type of exercise condition may be denoted as metastable equilibrium. Methods Thirty-three physically active male sport science students (age: 24.1 ± 3.8 years) were randomly assigned to a PT group (n = 13) exercising on stable (STAB) and a PT group (n = 20) on unstable surfaces (INST). Both groups trained countermovement jumps, drop jumps, and practiced a hurdle jump course. In addition, high bar squats were performed. Physical fitness tests on stable surfaces (hexagonal obstacle test, countermovement jump, hurdle drop jump, left-right hop, dynamic and static balance tests, and leg extension strength) were used to examine the training effects. Results Significant main effects of time (ANOVA) were found for the countermovement jump, hurdle drop jump, hexagonal test, dynamic balance, and leg extension strength. A significant interaction of time and training mode was detected for the countermovement jump in favor of the INST group. No significant improvements were evident for either group in the left-right hop and in the static balance test. Conclusions These results show that lower body PT on unstable surfaces is a safe and efficient way to improve physical performance on stable surfaces. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 606 KW - instability resistance training KW - stretch-shortening cycle KW - physical fitness test KW - balance training Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-429013 SN - 1866-8364 IS - 606 ER - TY - THES A1 - Lesinski, Melanie T1 - Modulating factors for drop jump performance T1 - Einflussfaktoren auf die Leistung im Niederhochsprung (Drop Jump) N2 - Background and objectives: Drop jumps (DJs) are well-established exercise drills during plyometric training. Several sports are performed under unstable surface conditions (e.g., soccer, beach volleyball, gymnastics). To closely mimic sport-specific demands, plyometric training includes DJs on both stable and unstable surfaces. According to the mechanical properties of the unstable surface (e.g., thickness, stiffness), altered temporal, mechanical, and physiological demands have been reported from previous cross-sectional studies compared with stable conditions. However, given that the human body simultaneously interacts with various factors (e.g., drop height, footwear, gender) during DJs on unstable surfaces, the investigation of isolated effects of unstable surface conditions might not be sufficient for designing an effective and safe DJ stimulus. Instead, the combined investigation of different factors and their interaction with surface instability have to be taken into consideration. Therefore, the present doctoral thesis seeks to complement our knowledge by examining the main and interaction effects of surface instability, drop height, footwear, and gender on DJ performance, knee joint kinematics, and neuromuscular activation. Methods: Healthy male and female physically active sports science students aged 19-26 years participated in the cross-sectional studies. Jump performance, sagittal and frontal plane knee joint kinematics, and leg muscle activity were measured during DJs on stable (i.e., firm force plate) and (highly) unstable surfaces (i.e., one or two AIREX® balance pads) from different drop heights (i.e., 20 cm, 40 cm, 60 cm) or under multiple footwear conditions (i.e., barefoot, minimal shoes, cushioned shoes). Results: Findings revealed that surface instability caused a DJ performance decline, reduced sagittal plane knee joint kinematics, and lower leg muscle activity during DJs. Sagittal plane knee joint kinematics as well as leg muscle activity decreased even more with increasing surface instability (i.e., two vs. one AIREX® balance pads). Higher (60 cm) compared to lower drop heights (≤ 40 cm) resulted in a DJ performance decline. In addition, increased sagittal plane knee joint kinematics as well as higher shank muscle activity were found during DJs from higher (60 cm) compared to lower drop heights (≤ 40 cm). Footwear properties almost exclusively affected frontal plane knee joint kinematics, indicating larger maximum knee valgus angles when performing DJs barefoot compared to shod. Between the different shoe properties (i.e., minimal vs. cushioned shoes), no significant differences during DJs were found at all. Only a few significant surface-drop height as well as surface-footwear interactions were found during DJs. They mainly indicated that drop height- and footwear-related effects are more pronounced during DJs on unstable compared to stable surfaces. In this regard, the maximum knee valgus angle was significantly greater when performing DJs from high drop heights (60 cm), but only on highly unstable surface. Further, braking and push-off times were significantly longer when performing DJs barefoot compared to shod, but only on unstable surface. Finally, analyses indicated no significant interactions with the gender factor. Conclusions: The findings of the present cumulative thesis indicate that stable rather than unstable surfaces as well as moderate (≤ 40 cm) rather than high (60 cm) drop heights provide sufficient stimuli to perform DJs. Furthermore, findings suggest that DJs on highly unstable surfaces (i.e., two AIREX® balance pads) from high drop heights (60 cm) as well as barefoot compared to shod seem to increase maximal knee valgus angle/stress by providing a more harmful DJ stimulus. Neuromuscular activation strategies appear to be modified by surface instability and drop height. However, leg muscle activity is only marginally effected by footwear and by the interactions of various external factors i.e., surface instability, drop height, footwear). Finally, gender did not significantly modulate the main or interaction effects of the observed external factors during DJs. N2 - Hintergrund und Ziele: Niederhochsprünge (Drop jumps [DJs]) sind wesentlicher Bestandteil vieler Sprungkrafttrainingsprogramme. Um sportartspezifisch zu trainieren und (natürliche) instabile Untergründe wie z. B. Sand, Gras oder Matten zu imitieren, werden DJs immer häufiger auch auf instabilen Unterlagen durchgeführt. Querschnittsstudien haben bereits die Effekte instabiler Unterlagen (z. B. AIREX® Balance Pad) auf DJs aufzeigen können. Da der menschliche Körper während der Ausführung von DJs auf instabilen Unterlagen jedoch noch mit weiteren (externen) Faktoren wie beispielsweise der Fallhöhe und dem Schuhwerk interagiert, ist eine kombinierte Betrachtung dieser Faktoren praxisrelevanter. Die vorliegende Doktorarbeit widmet sich daher den akuten Haupt- und Interaktionseffekten von Untergrundinstabilität, Fallhöhe, Schuhwerk und Geschlecht auf die Sprungleistung, die Kniegelenkskinematik sowie die Beinmuskelaktivierung während eines DJ. Methodik: An den Querschnittsschtudien nahmen gesunde männliche und weibliche Sportstudenten im Alter von 19 bis 26 Jahren teil. Während die Probanden DJs auf stabilien und (hochgradig) instabilen Unterlagen (d. h. ein oder zwei AIREX® Balance Pads), von verschiedenen Fallhöhen (d. h. 20cm, 40cm, 60cm) beziehungsweise mit unterschiedlichem Schuhwerk (d. h. barfuß, minimale Schuhe, gedämpfte Schuhe) durchführten, wurde die Sprungleistung, die Kniegelenkskinematik sowie die Beinmuskelaktivität erfasst. Ergebnisse: DJs auf instabilen im Vergleich zu stabilen Unterlagen führten zu einer signifikant geringeren Sprungleistung, einer geringeren maximalen Knieflexion sowie einer reduzierten Beinmuskelaktivit. Stieg die Untergrundsinstabilität (d. h. zwei vs. ein AIREX® Balance Pad), nahm die maximale Knieflexion und die Beinmuskelaktivität nochmals signifikant ab. Bei DJs von hohen (60 cm) im Vergleich zu moderaten Fallhöhen (≤ 40 cm) nahm die Sprungleistung ab, die maximale Knieflexion und Beinmuskelaktivität hingegen zu. Das Schuhwerk beeinflusste fast ausschließlich die Kniegelenkskinematik. Die Probanden valgisierten das Kniegelenk signifikant stärker, wenn sie barfuß und nicht mit Schuhen sprangen. Zwischen den zwei unterschiedlichen Schuhbedingungen konnte generell kein signifikanter Unterschied ermittelt werden. Die statistischen Analysen ergaben nur wenige signifikante Interaktionseffekte zwischen den untersuchten externen Faktoren. Diese zeigten relativ einheitlich, dass die fallhöhen- und schuhwerkspezifischen Effekte hauptsächlich bei DJs auf einer instabilen gegenüber einer stabilen Unterlage aufzufinden waren. So war der maximale Knievalguswinkel signifikant größer von einer hohen Fallhöhe (60 cm), aber nur auf (hochgradig) instabilen Unterlagen. Auch die Bodenkontaktzeit war signifikant länger, wenn barfuß anstatt mit Schuhen gesprungen wurde, aber nur auf instabilen Unterlagen. Das Geschlecht hatte keinen signifikanten Einfluss auf die akuten Haupt- und Interaktionseffekte der untersuchten externen Faktoren. Schlussfolgerung: Zusammenfassend zeigen die Ergebnisse, dass stabile gegenüber instabilen Unterlagen sowie moderate (≤ 40 cm) gegenüber hohen Fallhöhen (60 cm) bessere Voraussetzungen bei Sprungübungen zur Steigerung der Sprungleistung schaffen. Zudem scheinen DJs auf hochgradig instabilen Unterlagen von einer hohen Fallhöhe (60 cm) den maximalen Knievalguswinkel und damit auch den Stress für das vordere Kreuzband, zu erhöhen. Eine gesteigerte Knievalgisierung konnte auch beim barfüßigen Springen gegenüber DJs mit Schuhen aufgezeigt werden. Die Beinmuskelaktivität scheint in Abhängigkeit vom Untergrund und auch der Fallhöhe modifiziert zu werden, jedoch kaum für verschiedenes Schuhwerk. Das Geschlecht scheint die ermittelten Haupt- und Interaktionseffekte von Untergrundinstabilität, Fallhöhe und Schuhwerk nicht zusätzlich zu modulieren. KW - stretch-shortening cycle KW - electromyography KW - preactivation KW - short latency response KW - knee flexion angle KW - knee valgus angle KW - biomechanics KW - shoe KW - Dehnungsverkürzungszyklus KW - Elektromyografie KW - Voraktivierung KW - Reflexantwort KW - Knieflexion KW - Knievalgisierung KW - Biomechanik KW - Schuhe Y1 - 2019 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 - Negra, Yassine A1 - Chaabene, Helmi A1 - Fernandez-Fernandez, Jaime A1 - Sammoud, Senda A1 - Bouguezzi, Raja A1 - Prieske, Olaf A1 - Granacher, Urs T1 - Short-term plyometric Jump training improves repeated-sprint ability in prepuberal male soccer players JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - This study examined the effects of a short-term (i.e., 8 weeks) combined horizontal and vertical plyometric jump training (PJT) program in combination with regular soccer-specific training as compared with soccer-specific training only on jump and change of direction (CoD) performances, speed, and repeated-sprint ability (RSA) in prepuberal male soccer players. Twenty-four players were recruited and randomly assigned to either a PJT group (PJT(G); n = 13; 12.7 +/- 0.2 years) or an active control group (CONG; n = 11; 12.7 +/- 0.2 years). The outcome measures included tests for the assessment of jump performance (drop jump from 20- to 40-cm height [DJ20 and DJ40] and 3-hop test [THT]), speed (20-m sprint), CoD (T-test), and RSA (20-m repeated shuttle sprint). Data were analyzed using magnitude-based inferences. Within-group analyses revealed large performance improvements in the T-test (d = -1.2), DJ20 (d = 3.7), DJ40 (d = 3.6), THT (d = 0.6), and the RSA(total) (d = -1.6) in the PJT(G). Between-group analyses showed greater performance improvements in the T-test (d = -2.9), 20-m sprint time (d = -2.0), DJ20 (d = 2.4), DJ40 (d = 2.0), THT (d = 1.9), RSA(best) (d = -1.9), and the RSA(total) (d = -1.9) in the PJT(G) compared with CONG. Eight weeks of an in-season PJT in addition to regular soccer-specific training induced larger increases in measures of physical fitness in prepuberal male soccer players compared with regular soccer-specific training only. More specifically, PJT was effective in improving RSA performance. KW - youth KW - stretch-shortening cycle KW - athletic performance KW - soccer Y1 - 2020 U6 - https://doi.org/10.1519/JSC.0000000000002703 SN - 1064-8011 SN - 1533-4287 VL - 34 IS - 11 SP - 3241 EP - 3249 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Negra, Yassine A1 - Chaabene, Helmi A1 - Sammoud, Senda A1 - Bouguezzi, Raja A1 - Mkaouer, Bessem A1 - Hachana, Younes A1 - Granacher, Urs T1 - EFFECTS OF PLYOMETRIC TRAINING ON COMPONENTS OF PHYSICAL FITNESS IN PREPUBERAL MALE SOCCER ATHLETES: THE ROLE OF SURFACE INSTABILITY JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - Previous studies contrasted the effects of plyometric training (PT) conducted on stable vs. unstable surfaces on components of physical fitness in child and adolescent soccer players. Depending on the training modality (stable vs. unstable), specific performance improvements were found for jump (stable PT) and balance performances (unstable PT). In an attempt to combine the effects of both training modalities, this study examined the effects of PT on stable surfaces compared with combined PT on stable and unstable surfaces on components of physical fitness in prepuberal male soccer athletes. Thirty-three boys were randomly assigned to either a PT on stable surfaces (PTS; n = 17; age = 12.1 +/- 0.5 years; height = 151.6 +/- 5.7 cm; body mass = 39.2 +/- 6.5 kg; and maturity offset = 22.3 +/- 0.5 years) or a combined PT on stable and unstable surfaces (PTC; n = 16; age = 12.2 +/- 0.6 years; height = 154.6 +/- 8.1 cm; body mass = 38.7 +/- 5.0 kg; and maturity offset = 22.2 +/- 0.6 years). Both intervention groups conducted 4 soccer-specific training sessions per week combined with either 2 PTS or PTC sessions. Before and after 8 weeks of training, proxies of muscle power (e.g., countermovement jump [CMJ], standing long jump [SLJ]), muscle strength (e.g., reactive strength index [RSI]), speed (e.g., 20-m sprint test), agility (e.g., modified Illinois change of direction test [MICODT]), static balance (e.g., stable stork bal-ance test [SSBT]), and dynamic balance (unstable stork balance test [USBT]) were tested. An analysis of covariance model was used to test between-group differences (PTS vs. PTC) at posttest using baseline outcomes as covariates. No significant between-group differences at posttest were observed for CMJ (p > 0.05, d = 0.41), SLJ (p > 0.05, d = 0.36), RSI (p > 0.05, d = 0.57), 20-m sprint test (p > 0.05, d = 0.06), MICODT (p > 0.05, d = 0.23), and SSBT (p > 0.05, d = 0.20). However, statistically significant between-group differences at posttest were noted for the USBT (p < 0.01, d = 1.49) in favor of the PTC group. For most physical fitness tests (except RSI), significant pre-to-post improvements were observed for both groups (p < 0.01, d = 0.55-3.96). Eight weeks of PTS or PTC resulted in similar performance improvements in components of physical fitness except for dynamic balance. From a performance-enhancing perspective, PTC is recommended for pediatric strength and conditioning coaches because it produced comparable training effects as PTS on proxies of muscle power, muscle strength, speed, agility, static balance, and additional effects on dynamic balance. KW - youth KW - football KW - stretch-shortening cycle KW - athletic performance KW - balance Y1 - 2017 SN - 1064-8011 SN - 1533-4287 VL - 31 SP - 3295 EP - 3304 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Negra, Yassine A1 - Chaabene, Helmi A1 - Sammoud, Senda A1 - Prieske, Olaf A1 - Moran, Jason A1 - Ramirez-Campillo, Rodrigo A1 - Nejmaoui, Ali A1 - Granacher, Urs T1 - The increased effectiveness of loaded versus unloaded plyometric jump training in improving muscle power, speed, change of direction, and kicking-distance performance in prepubertal male soccer players JF - International journal of sports physiology and performance : IJSSP N2 - Purpose: To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Methods: Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7] y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5] y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie, countermovement jump, standing long jump); speed (ie, 5-, 10-, and 20-m sprint); CoD (ie, Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Results: Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33-0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00-0.09). Conclusion: Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players. KW - young KW - football KW - stretch-shortening cycle KW - maturity KW - athletic KW - performance Y1 - 2020 U6 - https://doi.org/10.1123/ijspp.2018-0866 SN - 1555-0265 SN - 1555-0273 VL - 15 IS - 2 SP - 189 EP - 195 PB - Human Kinetics CY - Champaign, Ill. ER - TY - JOUR A1 - Palma-Muñoz, Ignacio A1 - Ramírez-Campillo, Rodrigo A1 - Azocar-Gallardo, Jairo A1 - Álvarez, Cristian A1 - Asadi, Abbas A1 - Moran, Jason A1 - Chaabene, Helmi T1 - Effects of progressed and nonprogressed volume-based overload plyometric training on components of physical fitness and body composition variables in youth male basketball players JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - This study examined the effect of 6 weeks of progressed and nonprogressed volume-based overload plyometric training (PT) on components of physical fitness and body composition measures in young male basketball players, compared with an active control group. Subjects were randomly assigned to a progressed PT (PPT, n = 7; age = 14.6 +/- 1.1 years), a non-PPT (NPPT, n = 8, age = 13.8 +/- 2.0 years), or a control group (CG, n = 7, age = 14.0 +/- 2.0 years). Before and after training, body composition measures (muscle mass and fat mass), countermovement jump with arms (CMJA) and countermovement jump without arms (CMJ), horizontal bilateral (HCMJ) and unilateral jump with right leg (RJ) and left leg (LJ), 20-cm drop jump (DJ20), sprint speed (10 m sprint), and change of direction speed (CODS [i.e., T-test]) were tested. Significant effects of time were observed for muscle and fat mass, all jump measures, and CODS (all p < 0.01; d = 0.37-0.83). Significant training group x time interactions were observed for all jump measures (all p < 0.05; d = 0.24-0.41). Post hoc analyses revealed significant pre-post performance improvements for the PPT (RJ and LJ: increment 18.6%, d = 0.8 and increment 22.7%, d = 0.9, respectively; HCMJ: increment 16.4%, d = 0.8; CMJ: increment 22.4%, d = 0.7; CMJA: increment 23.3%, d = 0.7; and DJ20: increment 39.7%, d = 1.1) and for the NPPT group (LJ: increment 14.1%, d = 0.4; DJ20: increment 32.9%, d = 0.8) with greater changes after PPT compared with NPPT for all jump measures (all p < 0.05; d = 0.21-0.81). The training efficiency was greater (p < 0.05; d = 0.22) after PPT (0.015% per jump) compared with NPPT (0.0053% per-jump). The PPT induced larger performance improvements on measures of physical fitness as compared to NPPT. Therefore, in-season progressive volume-based overload PT in young male basketball players is recommended. KW - stretch-shortening cycle KW - young KW - team sports KW - athletic performance KW - anthropometry Y1 - 2021 U6 - https://doi.org/10.1519/JSC.0000000000002950 SN - 1064-8011 SN - 1533-4287 VL - 35 IS - 6 SP - 1642 EP - 1649 PB - Lippincott Williams & Wilkins CY - Philadelphia 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 - 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 -