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Ericksen HM, Earl-Boehm JE, Lally EM. The Effect of External Focus Versus Internal Focus Instruction on Jump-Landing Biomechanics in Healthy Females. J Athl Train 2024; 59:941-947. [PMID: 38291791 DOI: 10.4085/1062-6050-0154.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
CONTEXT There are different ways to deliver external focus (EF) and internal focus (IF) instruction. Understanding each modality better will help to develop more effective interventions to reduce injury risk. OBJECTIVES To investigate the difference in landing biomechanics between participants who received EF and IF instruction and control participants. A secondary aim was to evaluate participant perceptions of focus of attention. DESIGN Randomized controlled trial. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Forty-one healthy women (EF: n = 14, 23.0 ± 2.9 years, 1.69 ± 0.07 m, 64.0 ± 6.8 kg; IF: n = 15, 22.9 ± 3.2 years, 1.66 ± 0.08 m, 66.2 ± 12.4 kg; control: n = 12, 21.1 ± 2.9 years, 1.67 ± 0.11 m, 74.3 ± 15.1 kg). MAIN OUTCOME MEASURE(S) Participants scoring greater than or equal to 5 on the Landing Error Scoring System were allocated into the EF, IF, or control group. Knee and hip flexion and abduction were collected pre- and postintervention during 5 drop vertical jumps. For the intervention, each group was provided separate instructions. In between the intervention jumps, participants answered, "What strategy were you focusing on when completing the previous jump-landing trials?" Postintervention minus preintervention change scores were calculated, and separate 1-way analysis of variance assessments were performed to determine differences in the dependent variables. RESULTS Individuals in the EF group had a greater change in hip and knee flexion angles than individuals in the control group. There was no significant difference between the EF and IF groups for any variables. There were no significant differences in frontal plane variables. In the EF group, 71.4% aligned with the instructions given; in the IF group, 80% aligned; and in the control group, 50% aligned. CONCLUSIONS External focus instruction may not produce immediate changes in movement compared with IF instruction. Hip and knee flexion were greater in the EF group than in the control group but was not better than that in the IF group. Clinicians should provide instructions to patients, but the mode of instruction may not be as critical to see positive biomechanical changes. Patients may not always focus on the instruction being given; therefore, the relationship between instruction and patient experience should be further explored.
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Mills C, Exell TA, Wakefield-Scurr J, Jones MEA. Modelling the female torso and breast during physical activity: Implications on spinal loading. J Sports Sci 2024; 42:1453-1463. [PMID: 39189443 DOI: 10.1080/02640414.2024.2394748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 08/14/2024] [Indexed: 08/28/2024]
Abstract
Methods of modelling the female torso during physical activity often neglect the position and movement of the breast. This novel investigation compares three female torso modelling approaches that differ in complexity (integrated breast, fixed breast, dynamic breast) to determine the effect on spinal joint moments during running and jumping. The commonly used integrated breast model distributed breast mass within the torso, the fixed breast model attached the mass of the breasts to fixed positions on the anterior of the torso, and a new dynamic breast model enabled relative motion between the breasts and anterior torso. Key findings demonstrated minimal differences in lumbar spine moments (<0.05 Nm/kg; 4%) between integrated breast and fixed breast models but greater differences, up to 0.86 Nm/kg (68%) during running and 0.89 Nm/kg (82%) during jumping, when breast motion was included. Thoracic spine moments revealed similar patterns with minimal differences (<0.05 Nm/kg; 11%) between integrated breast and fixed breast models and greater differences, up to 0.48 Nm/kg (92%) during running and 0.63 Nm/kg (66%) during jumping, with the dynamic breast model. Future female musculoskeletal models should consider including breast mass and motion to avoid mis-representing spinal loading in females during running and jumping.
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Affiliation(s)
- Chris Mills
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Timothy A Exell
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | | | - Melissa E A Jones
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
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3
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Pinto BL, Callaghan JP. Improving the estimation of countermovement jump height from force plate recordings by considering the interaction between multiple procedural steps: An optimisation approach. J Sports Sci 2024:1-8. [PMID: 39023353 DOI: 10.1080/02640414.2024.2381288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 07/10/2024] [Indexed: 07/20/2024]
Abstract
Force plates are used as standalone measurement systems in research and practice to evaluate metrics such as jump height. Calculating jump height involves multiple procedural steps, but previous investigations aiming to improve calculation procedures have only considered the influence of a single procedural step in isolation. The purpose of this study was to investigate if considering the interacting influence of multiple procedural steps in conjunction would impact the accuracy of jump height calculated from force plate recordings. An optimisation procedure was used to determine the combination of filter type, filter order, filter cut-off, integration start point and instant of take-off, that would minimize the root mean squared difference between force plate calculated jump height and a kinematic criterion. The best filter approach was a fifth order Butterworth filter with a 6 Hz cut-off frequency or a third order Chebyshev filter with a 5 Hz cut-off frequency. The best starting point for integration was approximately 0.25 s prior to the onset of the jump and the instant of take-off was best identified by finding the first instant that the force-time signal decreased by the magnitude of system weight. The presented optimisation technique provides an improved quantitative approach to develop standard procedures.
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Affiliation(s)
- Brendan L Pinto
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Jack P Callaghan
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada
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4
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Xu J, Turner A, Comyns TM, Chavda S, Bishop C. Effects of external verbal cueing on countermovement rebound jump performance. Sports Biomech 2024:1-19. [PMID: 39007935 DOI: 10.1080/14763141.2024.2377217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024]
Abstract
This study examined the effects of three external verbal cues on countermovement rebound jump (CMRJ) performance. Twenty-five recreational athletes completed nine jumps with distinct height, velocity and combined cue focus. A general linear model analysis of variance was used to evaluate systematic bias between conditions (p < 0.05). The height and velocity cues significantly altered jump height and contact times in both jumps during the CMRJ, respectively (p ≤ 0.002). The combined cue significantly reduced contact time while increasing leg stiffness compared to the height cue (p ≤ 0.038). It also increased jump height compared to the velocity cue (p ≤ 0.005) in both jumps, resulting in the highest explosive power and reactive strength values among all conditions. Furthermore, the combined cue enhanced the positive ankle contribution compared to the height cue (p = 0.020) and increased positive hip and negative knee joint work compared to the velocity cue (p ≤ 0.040) in the second jump of the CMRJ. These findings advise practitioners to use the height cue to maximise jump height, the velocity cue to minimise contact times and the combined cue to maximise explosive power and reactive strength.
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Affiliation(s)
- Jiaqing Xu
- London Sport Institute, Middlesex University, London, UK
| | - Anthony Turner
- London Sport Institute, Middlesex University, London, UK
| | - Thomas M Comyns
- Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland
| | - Shyam Chavda
- London Sport Institute, Middlesex University, London, UK
| | - Chris Bishop
- London Sport Institute, Middlesex University, London, UK
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5
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Brown F, Hill M, Renshaw D, Tallis J. Force-Time Characteristics of Repeated Bouts of Depth Jumps and the Effects of Compression Garments. J Appl Biomech 2024; 40:217-231. [PMID: 38580303 DOI: 10.1123/jab.2023-0221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/22/2024] [Accepted: 02/14/2024] [Indexed: 04/07/2024]
Abstract
No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0.6 m. Exercise was repeated after 14 days. Using a 3-way (set × bout × group) design, changes in GRF were assessed with analysis of variance and statistical parametric mapping. Jump height, reactive strength, peak, and mean propulsive forces declined between sets (P < .001). Vertical stiffness, contact time, force at zero velocity, and propulsive duration increased (P < .05). According to statistical parametric mapping, braking (17%-25% of the movement) and propulsive forces (58%-81%) declined (P < .05). During the repeated bout, peak propulsive force and duration increased (P < .05), while mean propulsive force (P < .05) and GRF from 59% to 73% declined (P < .001). A repeated bout of DJs differed in propulsive GRF, without changes to the eccentric phase, or effects from CG.
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Affiliation(s)
- Freddy Brown
- Research Centre for Physical Activity, Sport and Exercise Science, Coventry University, Coventry, United Kingdom
- School of Life Sciences, Coventry University, Coventry, United Kingdom
| | - Matt Hill
- Research Centre for Physical Activity, Sport and Exercise Science, Coventry University, Coventry, United Kingdom
| | - Derek Renshaw
- Centre for Health and Life Sciences, Coventry University, Coventry, United Kingdom
| | - Jason Tallis
- Research Centre for Physical Activity, Sport and Exercise Science, Coventry University, Coventry, United Kingdom
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6
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Furuhashi Y, Hioki Y, Maemura H, Hayashi R. External Focus Affects Drop Jump Performance: Focusing on Different Aims and Words of Instruction. J Hum Kinet 2023; 89:33-41. [PMID: 38053950 PMCID: PMC10694714 DOI: 10.5114/jhk/159235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 02/16/2023] [Indexed: 12/07/2023] Open
Abstract
Attentional focus strategies eliciting external focus of attention effectively enhance drop jump (DJ) performance, however, their effects vary depending on the words used for the instructions. We aimed to examine the effects of different words on DJ performance using instructions eliciting external focus to minimize contact time (CT) or maximize jump height (JH). Twenty collegiate athletes performed DJs from a 30-cm platform after receiving one of the four instructions: two instructions (COND 1 and 2) about minimizing CT, and two instructions (COND 3 and 4) about maximizing JH. The reactive strength index (RSI), CT, JH, relative peak vertical ground reaction force (vGRF), and leg stiffness (kvert) were compared between conditions using repeated-measures analysis of variance. There was no significant main effect of conditions on the RSI, relative peak vGRF, and kvert (p > 0.05). CT was significantly shorter under CONDs 1 and 2 than COND 3 (p < 0.05); JH was significantly higher under COND 3 than CONDs 1 and 2 (p < 0.05), and under COND 4 than COND 1 (p < 0.05). When using attentional focus strategies in DJ, it is necessary to use different words and purposes according to the players' tasks.
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Affiliation(s)
- Yuki Furuhashi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Yusuke Hioki
- Joint Graduate School in Science of School Education, Hyogo University of Teacher Education, Hyogo, Japan
| | - Hirohiko Maemura
- Faculty of Health and Sports Science, University of Tsukuba, Ibaraki, Japan
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Loturco I, Pereira LA, Freitas TT, Moura TBMA, Mercer VP, Fernandes V, Moura NSA, Moura NA, Zając A, Bishop C. Plyometric Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights. J Hum Kinet 2023; 87:131-150. [PMID: 37559773 PMCID: PMC10407309 DOI: 10.5114/jhk/169167] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/12/2023] [Indexed: 08/11/2023] Open
Abstract
Plyometric training is extensively used by coaches to enhance neuromuscular performance in a wide variety of sports. Due to the high demands of sprint speed and power output in elite sprinters and jumpers, sprint and jump coaches are likely to have great knowledge on this topic. Undoubtedly, this expertise is even more pronounced for Olympic coaches, who work with some of the fastest and most powerful athletes in the world, and who are required to continually maintain these athletes at optimal performance levels. Describing and discussing the practices commonly adopted by these coaches in detail and extrapolating this experience to other sport coaching contexts and disciplines may be extremely relevant. The current article presents, explores, and illustrates the plyometric training practices of Brazilian Olympic sprint and jump coaches, with a special focus on training programming and exercise selection.
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Affiliation(s)
- Irineu Loturco
- NAR—Nucleus of High Performance in Sport, São Paulo, Brazil
- Department of Human Movement Sciences, Federal University of São Paulo, São Paulo, Brazil
- University of South Wales, Pontypridd, Wales, United Kingdom
| | - Lucas A. Pereira
- NAR—Nucleus of High Performance in Sport, São Paulo, Brazil
- Department of Human Movement Sciences, Federal University of São Paulo, São Paulo, Brazil
| | - Tomás T. Freitas
- NAR—Nucleus of High Performance in Sport, São Paulo, Brazil
- Department of Human Movement Sciences, Federal University of São Paulo, São Paulo, Brazil
- UCAM Research Center for High Performance Sport, UCAM Universidad Católica de Murcia, Murcia, Spain
- Facultad de Deporte, UCAM Universidad Católica de Murcia, Murcia, Spain
| | | | | | | | | | - Nélio A. Moura
- Pinheiros Sport Club, São Paulo, Brazil
- Chinese Athletics Association, Beijing, China
| | - Adam Zając
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education in Katowice, Katowice, Poland
| | - Chris Bishop
- London Sport Institute, Middlesex University, London, United Kingdom
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Barillas SR, Oliver JL, Lloyd RS, Pedley JS. Kinetic Responses to External Cues Are Specific to Both the Type of Cue and Type of Exercise in Adolescent Athletes. J Strength Cond Res 2023; 37:597-605. [PMID: 35876438 DOI: 10.1519/jsc.0000000000004307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Barillas, SR, Oliver, JL, Lloyd, RS, and Pedley, J. Kinetic responses to external cues are specific to both the type of cue and type of exercise in adolescent athletes. J Strength Cond Res 37(3): 597-605, 2023-The purpose of this study was to examine how external cues influence kinetics during isometric and dynamic tasks in adolescent athletes. Fifteen adolescent male soccer players performed an isometric midthigh pull (IMTP), unloaded and loaded squat jumps (SJs) (15 and 30% of body mass), countermovement jump (CMJ), and drop jump (DJ) using a neutral or external force-specific or velocity-specific cues. Cue type had limited effects on outcomes in the IMTP or SJs, with mostly trivial ( g < 0.20), nonsignificant differences ( p > 0.05) across kinetic variables. In the CMJ and DJ, a force cue significantly ( p < 0.05) increased jump height ( g = 0.43 & 0.52) compared with a velocity cue, but in the DJ, a force cue significantly increased jump height ( g = 0.52) compared with both a neutral and velocity cue. However, a velocity cue significantly ( p < 0.05) reduced ground contact time ( g = 0.73-1.52) and time to peak force ( g = 0.50-1.29) in both the CMJ and DJ when compared with a force and neutral cue and increased force and power-related measures ( g = 0.33-1.12) in the CMJ and DJ when compared with a force cue. In adolescent athletes, the type of external cue had limited effects on kinetic measures in an IMTP and SJ but differential effects on both a CMJ and DJ, suggesting cues have more effect with increasing movement velocity. Consequently, practitioners working with adolescent athletes should consider both the type of exercise and the desired outcome when providing external cues.
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Affiliation(s)
- Saldiam R Barillas
- Sport, Exercise and Physical Activity Research Group, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
- Youth Physical Development Centre, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Jon L Oliver
- Youth Physical Development Centre, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand; and
| | - Rhodri S Lloyd
- Youth Physical Development Centre, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand; and
- Centre for Sport Science and Human Performance, Waikato Institute of Technology, Hamilton, New Zealand
| | - Jason S Pedley
- Youth Physical Development Centre, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
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9
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Furuhashi Y, Hioki Y, Yoshimoto S, Hayashi R. Effect of Neutral, Internal, and External Focus on Drop Jump Performance: Is Drop Jump Performance Affected by Plyometric Training Experience? J Strength Cond Res 2022; 36:3319-3323. [PMID: 34593726 DOI: 10.1519/jsc.0000000000004147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT Furuhashi, Y, Hioki, Y, Yoshimoto, S, and Hayashi, R. The effect of neutral, internal, and external focus on drop jump performance: is drop jump performance affected by plyometric training experience? J Strength Cond XX(X): 000-000, 2021-Providing an external focus of attention through verbal instructions can improve the drop jump (DJ) performance, which differs based on the skill level of athletes. The purpose of this study was to assess the effect of change of focus of attention on the performance of DJs in experienced and inexperienced athletes. Thirty-eight male collegiate athletes divided into the experienced group (E group: age, 21.5 ± 1.4 years; height, 173.4 ± 5.7 cm; and body mass, 65.7 ± 6.2 kg) and the inexperienced group (I group: age, 21.9 ± 1.5 years; height, 172.8 ± 5.1 cm; and body mass, 68.7 ± 5.5 kg) performed 2 trials of DJs after listening to instructions designed to evoke a neutral, internal, or external focus of attention. Contact time (CT), jump height (JH), reactive strength index (RSI), and leg-spring stiffness (k vert ) were recorded during DJ and compared between the 2 groups using a repeated-measures analysis of variance. In the E group, the neutral condition was associated with a significantly higher RSI, JH, and k vert than the internal and external conditions ( p < 0.05). In the I group, the external condition was associated with significantly higher RSI and k vert and shorter CT than other conditions ( p < 0.05). Therefore, this suggests that attentional focus strategies need to be selected depending on DJ experience: A neutral focus may be preferable for athletes experienced in DJs, whereas an external focus may be more suitable for athletes with lesser DJ experience.
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Affiliation(s)
- Yuki Furuhashi
- Graduate School of Education, Gifu University, Gifu, Japan
| | - Yusuke Hioki
- Joint Graduate School in Science of School Education, Hyogo University of Teacher Education, Hyogo, Japan; and
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10
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Panoutsakopoulos V, Chalitsios C, Nikodelis T, Kollias IA. Kinetic time-curves can classify individuals in distinct levels of drop jump performance. J Sports Sci 2022; 40:2143-2152. [PMID: 36309478 DOI: 10.1080/02640414.2022.2140921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study examined whether analysing kinetic features of drop jumps (DJ) as one-dimensional biomechanical curves can reveal specific patterns that are consistent and can cluster DJ performance. Hierarchical clustering analysis on DJ from 40 cm data performed by 128 physically active male participants (23.0 ± 4.5 yrs, 1.84 ± 0.07 m, 79.1 ± 10.8 kg) was performed on the derived time-normalised force, power and vertical stiffness curves to unmask the underlying patterns and to explore the dissimilarities identified from the subgroup (cluster) analysis. Results revealed poor, average and top DJ performers. Top performers exhibited larger peak force, power and vertical stiffness compared to the other two groups, and the poor performers had lower values compared to the average performers (p < .05). The time curves of force, power and vertical stiffness exhibited between cluster dissimilarities from ~25% to ~70%, and ~20% to 40% plus ~55% to 70% from the beginning of the ground contact, respectively. The force and power time-curves distinguished DJ ability similarly since they shared 69% of the cases in the top performers' cluster. The content of cases (membership) for vertical stiffness was different from the membership for the force and power time-curve clusters. In conclusion, stiffness should be considered during plyometric training, but does not distinctly define DJ performance.
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Affiliation(s)
- Vassilios Panoutsakopoulos
- Biomechanics Laboratory, School of Physical Education and Sports Sciences at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Christos Chalitsios
- Biomechanics Laboratory, School of Physical Education and Sports Sciences at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Thomas Nikodelis
- Biomechanics Laboratory, School of Physical Education and Sports Sciences at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Iraklis A Kollias
- Biomechanics Laboratory, School of Physical Education and Sports Sciences at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Louder T, Thompson BJ, Bressel E. Association and Agreement between Reactive Strength Index and Reactive Strength Index-Modified Scores. Sports (Basel) 2021; 9:sports9070097. [PMID: 34357931 PMCID: PMC8309746 DOI: 10.3390/sports9070097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/21/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
Since the reactive strength index (RSI) and reactive strength index-modified (RSI-mod) share similar nomenclature, they are commonly referred as interchangeable measures of agility in the sports research literature. The RSI and RSI-mod are most commonly derived from the performance of depth jumping (DJ) and countermovement jumping (CMJ), respectively. Given that DJ and CMJ are plyometric movements that differ materially from biomechanical and neuromotor perspectives, it is likely that the RSI and RSI-mod measure distinct aspects of neuromuscular function. The purpose of this investigation was to evaluate the association and agreement between RSI and RSI-mod scores. A mixed-sex sample of NCAA division I basketball athletes (n = 21) and active young adults (n = 26) performed three trials of DJ from drop heights of 0.51, 0.66, and 0.81 m and three trials of countermovement jumping. Using 2-dimensional videography and force platform dynamometry, RSI and RSI-mod scores were estimated from DJ and CMJ trials, respectively. Linear regression revealed moderate associations between RSI and RSI-mod scores (F = 11.0–38.1; R2 = 0.20–0.47; p < 0.001–0.001). Bland–Altman plots revealed significant measurement bias (0.50–0.57) between RSI and RSI-mod scores. Bland–Altman limit of agreement intervals (1.27–1.51) were greater than the mean values for RSI (0.97–1.05) and RSI-mod (0.42) scores, suggesting poor agreement. Moreover, there were significant performance-dependent effects on measurement bias, wherein the difference between and the mean of RSI and RSI-mod scores were positively associated (F = 77.2–108.4; R2 = 0.63–0.71; p < 0.001). The results are evidence that the RSI and RSI-mod cannot be regarded as interchangeable measures of reactive strength.
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Affiliation(s)
- Talin Louder
- Department of Kinesiology and Health Science, Utah State University, Logan, UT 84322, USA; (B.J.T.); (E.B.)
- Dennis G. Dolny Movement Research Clinic, Sorenson Legacy Foundation Center for Clinical Excellence, Utah State University, Logan, UT 84322, USA
- Correspondence:
| | - Brennan J. Thompson
- Department of Kinesiology and Health Science, Utah State University, Logan, UT 84322, USA; (B.J.T.); (E.B.)
- Dennis G. Dolny Movement Research Clinic, Sorenson Legacy Foundation Center for Clinical Excellence, Utah State University, Logan, UT 84322, USA
| | - Eadric Bressel
- Department of Kinesiology and Health Science, Utah State University, Logan, UT 84322, USA; (B.J.T.); (E.B.)
- Dennis G. Dolny Movement Research Clinic, Sorenson Legacy Foundation Center for Clinical Excellence, Utah State University, Logan, UT 84322, USA
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12
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Oliver JL, Barillas SR, Lloyd RS, Moore I, Pedley J. External Cueing Influences Drop Jump Performance in Trained Young Soccer Players. J Strength Cond Res 2021; 35:1700-1706. [PMID: 30676388 DOI: 10.1519/jsc.0000000000002935] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Oliver, JL, Barillas, SR, Lloyd, RS, Moore, I, and Pedley, J. External cueing influences drop jump performance in trained young soccer players. J Strength Cond Res 35(6): 1700-1706, 2021-Drop jump (DJ) characteristics provide insight on power production and injury risk. The purpose of this study was to investigate the effect of external cueing on DJ characteristics in young male soccer players. Fourteen academy soccer players performed DJs with 4 different conditions, control (CONT), contact cue (CC), height cue (HC), and quiet cue (QC). Performance measures were reactive strength index (RSI), jump height, ground contact time (GCT), and take-off impulse, with injury risk reflected by impact peak, impact timing, and landing impulse. Contact cue showed a very large significant reduction in GCT (effect size [ES] > 2.0, p < 0.05), and moderate to large increase in RSI, landing impulse, and push-off impulse (ES 0.70-1.55, p < 0.05) compared with all other conditions. Contact cue also moderately increased impact peak when compared with HC and QC (ES ≥ 0.78, p < 0.05). Height cue led to a significant increase in jump height that was moderately greater than other external cues (ES ≥ 0.87, p < 0.05), but with only a small nonsignificant increase compared (ES 0.54, p > 0.05) with CONT. The data showed that all cues provided a specific response; CC reduced GCT and increased RSI, HC increased jump height, and QC reduced outcomes associated with injury risk. Height cue may be advantageous for young soccer players with a low training age because it shows a small to moderate increase in jump height without increasing injury risk. Young players may need to be safely progressed to be able to use a CC to facilitate high reactive strength without being exposed to undue injury risk.
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Affiliation(s)
- Jon L Oliver
- Youth Physical Development Center, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff Wales, United Kingdom.,Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand; and
| | - Saldiam R Barillas
- Youth Physical Development Center, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff Wales, United Kingdom
| | - Rhodri S Lloyd
- Youth Physical Development Center, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff Wales, United Kingdom.,Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand; and.,Center for Sport Science and Human Performance, Waikato Institute of Technology, Hamilton, New Zealand
| | - Isabel Moore
- Youth Physical Development Center, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff Wales, United Kingdom
| | - Jason Pedley
- Youth Physical Development Center, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff Wales, United Kingdom
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The effects of drop vertical jump technique on landing and jumping kinetics and jump performance. J Electromyogr Kinesiol 2021; 56:102504. [DOI: 10.1016/j.jelekin.2020.102504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/28/2020] [Accepted: 11/11/2020] [Indexed: 11/21/2022] Open
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14
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Scarr T, Oranchuk DJ, Rafferty D. Comparison of drop jump force-time profiles of team sport athletes and active controls. MOTRIZ: REVISTA DE EDUCACAO FISICA 2021. [DOI: 10.1590/s1980-657420210015121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Thomas Scarr
- School of Health and Life Sciences, Glasgow Caledonian University, Scotland
| | - Dustin J Oranchuk
- Sports Performance Research Institute New Zealand, Auckland University of Technology, New Zealand; Institute of Health and Sport, Victoria University, Australia
| | - Daniel Rafferty
- School of Health and Life Sciences, Glasgow Caledonian University, Scotland
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15
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Influence of Coaching Condition on the Magnitude and Reliability of Drop Jump Height in Men and Women. Motor Control 2020; 25:167-181. [PMID: 33348318 DOI: 10.1123/mc.2020-0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 10/03/2020] [Accepted: 10/04/2020] [Indexed: 11/18/2022]
Abstract
This study examined the effect of different coaching conditions on the magnitude and reliability of drop jump height in men and women. Nineteen collegiate sport sciences students (10 men) performed two sets of 10 drop jumps under four different coaching conditions: neutral, augmented feedback, external focus of attention, and a combination of augmented feedback and external focus of attention. The augmented feedback condition revealed a significantly higher jump height than the neutral condition (p = .002), while no significant differences were observed for the remaining conditions (p ≥ .38). The external focus of attention condition was more reliable than the neutral and augmented feedback conditions (coefficient of variationratio ≥ 1.15), while no differences were observed between the remaining conditions. These results suggest that both the magnitude and reliability of the drop jump height performance are influenced by the coaching condition.
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16
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Landing Error Scoring System scores change with knowledge of scoring criteria and prior performance. Phys Ther Sport 2020; 46:155-161. [PMID: 32942243 DOI: 10.1016/j.ptsp.2020.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To examine if the knowledge of scoring criteria and prior performance influence Landing Error Scoring System (LESS) outcomes. DESIGN Cross-sectional. SETTING Laboratory. PARTICIPANTS Thirty individuals. MAIN OUTCOME MEASURES The LESS was tested at Baseline and one week later under two conditions: Pre and Post information. For the Post condition, LESS items were explained to participants, as were their individual Baseline scores. Mean LESS scores and number of individuals categorized at high and low risk were compared between Pre and Post using paired t-tests and McNemar's tests, respectively. McNemar's tests were also used to compare proportions of specific LESS errors between Pre and Post conditions. RESULTS Mean LESS Post scores (4.7 ± 1.2 errors) were significantly lower than Pre scores (6.6 ± 2.0 errors, p < 0.001) as was the number of individuals at high risk (25 vs 10 participants, p < 0.001). A significantly lower proportion of participants scored an error for the joint displacement item of LESS Post compared to Pre condition (p < 0.001). CONCLUSION When using the LESS, it is important that tested individuals have no knowledge of scoring criteria or previous errors for a valid assessment of innate jump-landing movement patterns and injury risk.
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Frayne DH, Zettel JL, Beach TAC, Brown SHM. The Influence of Countermovements on Inter-Segmental Coordination and Mechanical Energy Transfer during Vertical Jumping. J Mot Behav 2020; 53:545-557. [PMID: 32862794 DOI: 10.1080/00222895.2020.1810611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Inter-segmental coordination patterns and mechanical energy transfer were compared between vertical jumping tasks which possess different countermovement characteristics. Thirteen participants completed squat (SJ), countermovement (CMJ) and drop (DVJ) vertical jumps. Inter-segmental coordination patterns became more out-of-phase with increases in countermovement velocity (DVJ > CMJ > SJ), at the ankle, hip and lumbar spine (all p < 0.05), but not at the knee. With countermovements, more inter-segmental energy transfer occurred at all joints (p < 0.05), but increasing the countermovement velocity (DVJ compared to CMJ) did not always increase energy transfer (p < 0.001 for the hip and knee, p > 0.05 for the ankle and lumbar spine). The relationship between mechanical energy transfer and inter-segmental coordination patterns during vertical jumping is not straightforward since the responses to these varying countermovement demands were not consistent across all joints.
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Affiliation(s)
- Devon H Frayne
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - John L Zettel
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Tyson A C Beach
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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18
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Barillas SR, Oliver JL, Lloyd RS, Pedley JS. Cueing the Youth Athlete During Strength and Conditioning: A Review and Practical Application. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Multi-Segmental Motion in Foot during Counter-Movement Jump with Toe Manipulation. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10051893] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human toes are crucial for vertical jumping performance. The purpose of this study is to investigate the acute effect of hallux abduction manipulation on foot inter-segment kinematic alterations and plantar loading redistribution during the countermovement jump (CMJ). Thirteen participants were recruited to join in this experiment, for the collection of the foot inter-segment kinematics and plantar pressure data. During the take-off phase, the contact area presented a significant increase while the pressure-time integral decreased in the second metatarsal (M2), whilst the third metatarsal (M3) and fourth metatarsal (M4) decreased significantly in pressure-time integral with Toe-Manipulation (TM). During the landing phase, maximum force and peak pressure were smaller in the big toe (BT) after hallux abduction manipulation. HXFFA (hallux-forefoot angle) showed a greater pronation after manipulation in the frontal plane (0%–26% and 50%–100%) with p = 0.002 and p < 0.001. In the transverse plane, the smaller adductions were found during 62%–82% in take-off and 62%–91% in landing (p = 0.003 and p < 0.001). There was a redistributed plantar loading during the landing phase from the medial to lateral forefoot. However, a reduced hallux range of motion in the TM session was exhibited, compared to Non-Toe-Manipulation (NTM).
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20
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Myoelectric Responses of Lower-Body Muscles Performing Squat and Lunge Exercise Variations Adopting Visual Feedback With a Laser Sensor. J Sport Rehabil 2020; 29:1159-1165. [PMID: 31945738 DOI: 10.1123/jsr.2019-0194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/30/2019] [Accepted: 11/25/2019] [Indexed: 11/18/2022]
Abstract
STUDY DESIGN Cross-over study. CONTEXT The squat, single-leg squat, forward lunge, and reverse lunge are fundamental movements often performed in activities of daily living, sports competitions, and sport-specific training. OBJECTIVE The purpose of this study was to investigate the effect of visual feedback with a laser sensor (VFLS) versus a control condition on the myoelectric activity (surface electromyography [sEMG]) of the vastus medialis oblique (VMO), vastus lateralis, gluteus medius (Gmed), and erector spinae muscles during the performance of several squat variations with bodyweight. METHODS Nineteen female college students (20 [2.5] y, 165.3 [10.2] cm, 66.4 [4.1] kg, 2 [1.2] y of resistance training experience) with a background in strength or sports training volunteered to participate in this study. Over 4 separate visits, subjects performed 2 sets of 10 repetitions of a squat variation exercise in random order (ie, squat, single-leg squat, forward lunge, and reverse lunge). The first set of a given squat variation condition was considered a control set, and then after 3-minute rest, a second set was performed with VFLS. RESULTS Significant decreases in VMO and Gmed myoelectric activity were observed during the VFLS set versus the control set for the forward lunge exercise (P = .03). No differences were observed between the control set and VFLS set in the sEMG normalized signal for all muscles analyzed for the squat and single-leg squat, respectively. However, the sample entropy of the sEMG signal for the erector spinae became more irregular during the VFLS set versus the control set for the squat exercise (P = .01), whereas the Gmed presented a more irregular sEMG signal during the VFLS set versus the control set for the single-leg squat (P = .08). CONCLUSION Laser sensor biofeedback may induce significant decreases in VMO and Gmed activation performing forward lunge exercise. Therefore, laser sensor biofeedback may induce a reduction in muscle activity of neutralizers muscles during a few squat bodyweight variations (bilateral, single-leg, forward, and reverse lunge).
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21
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The Effects of Instruction Exercises on Performance and Kinetic Factors Associated With Lower-Extremity Injury in Landing After Volleyball Blocks. J Sport Rehabil 2020; 29:51-64. [PMID: 30526280 DOI: 10.1123/jsr.2018-0163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 10/15/2018] [Accepted: 10/28/2018] [Indexed: 11/18/2022]
Abstract
CONTEXT Female volleyball players are more predisposed to anterior cruciate ligament injury in comparison with their male counterparts. Recent research on anterior cruciate ligament injury prevention strategies has shown the positive results of adopting the external focus (EF) of attention in sports. OBJECTIVE To determine the effect of 6-week EF instruction exercises on performance and kinetic factors associated with lower-extremity injury in landing after the volleyball blocks of female athletes. DESIGN Pretest and posttest control study. SETTING University research laboratory. PARTICIPANTS Thirty-two female volleyball players (18-24 y old) from the same team randomly divided into experimental (n = 16) and control (n = 16) groups. INTERVENTION The experimental group performed a 6-week exercise program with EF instructions. The control group continued its regular volleyball team schedule. MAIN OUTCOME MEASURES To assess function, single-leg triple hop test for distance was used. A force plate was used to evaluate kinetic variables including vertical ground reaction forces, the rate of loading, and dynamic postural stability index. All data were assessed at baseline and after the intervention. RESULTS There was a significant increase in single-leg triple hop test (P < .05) and in the first and second peak ground reaction force, rate of loadings, dynamic postural stability index (P < .05). CONCLUSION According to the results of this study, anterior cruciate ligament injury prevention programs should incorporate EF instruction exercises to enhance the kinetics and to increase athletes' functional performance.
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22
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Chan VCH, Welsh TN, Frost DM, Beach TAC. Using visual aids to influence manual lifting techniques: acute effects of viewing static images on spine motion. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2019; 27:605-612. [PMID: 31112070 DOI: 10.1080/10803548.2019.1620489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose. This study aimed to determine whether untrained observers alter their spine as directed via static images of different lifting techniques. Methods. Ten men and eight women, who had no lifting or visual observation training, performed box lifts. Following a self-selected lifting technique trial, participants performed four experimental lifting trials (in randomized order) wherein they were instructed to execute lifts in accordance with the techniques pictured. These techniques differed by the amount of knee, trunk and spine flexion modeled. Peak lumbar flexion angles and flexion/extension velocities were quantified, and then statistically analyzed via general linear models with two within-participant factors (condition = technique; phase = lift/lower). Results. Lumbar flexion angles and flexion/extension velocities differed between conditions (p < 0.001), although the effects depended on the combination of postural characteristics pictured. A main effect of phase was observed for peak lumbar flexion velocity only (p = 0.001). No condition × phase interaction effects were detected for any dependent variables (p > 0.050). Conclusions. Acute changes in lifting mechanics can be elicited via visual observation of pictured techniques. However, if using pictures to attenuate peak lumbar flexion displacements and velocities when lifting, auxiliary instruction may be needed to direct observers' attention to the spine curvature displayed.
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Affiliation(s)
- Victor C H Chan
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
| | - Timothy N Welsh
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada.,Centre for Motor Control, University of Toronto, Canada
| | - David M Frost
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
| | - Tyson A C Beach
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada.,Centre for Motor Control, University of Toronto, Canada
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23
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Comyns TM, Brady CJ, Molloy J. Effect of Attentional Focus Strategies on the Biomechanical Performance of the Drop Jump. J Strength Cond Res 2019; 33:626-632. [PMID: 30789857 DOI: 10.1519/jsc.0000000000003009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Comyns, TM, Brady, CJ, and Molloy, J. Effect of attentional focus strategies on the biomechanical performance of the drop jump. J Strength Cond Res 33(3): 626-632, 2019-Motor performance can be influenced by focusing an athlete's attention through the use of verbal instructions. There is limited research on the effect of internal, neutral, and external attentional focus strategies on drop jump (DJ) performance aimed at maximizing height jumped (HJ) and minimizing ground contact time (CT). The purpose of this study was to assess the effect of attentional focus strategies on biomechanical variables related to efficient DJ performance, namely HJ, CT, reactive strength index (RSI), leg-spring stiffness, and peak and relative peak ground reaction force (GRF). Seventeen male recreationally trained subjects performed 2 DJs after listening to instructions designed to evoke an internal, external, or neutral attentional focus. In total, 6 DJs were performed in the testing session, and the order of the instructions was randomly assigned. Significance was set at p ≤ 0.05. Results indicated that, compared with the neutral strategy, the external focus resulted in significantly higher RSI (p = 0.046), peak GRF (p = 0.025), relative GRF (p = 0.02), and leg-spring stiffness (p = 0.02). No significant difference was seen in DJ CT and HJ between all 3 conditions (p ≥ 0.05). These results indicate that the use of an external focus of attention may potentially result in a more effective and efficient fast stretch-shortening cycle performance because of the augmentation of RSI and leg stiffness. More research is warranted, however, because of the lack of significant results pertaining to CT and HJ.
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Affiliation(s)
- Thomas M Comyns
- Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.,Health Research Institute, University of Limerick, Limerick, Ireland
| | - Claire J Brady
- Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland
| | - James Molloy
- Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland
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24
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Yokoyama H, Oda A, Makino M, Ishikawa T, Shikanai K, Tsukamoto T, Tsuda E. Effects of different oral instructions on kinematic and kinetic parameters during drop vertical jump. J Phys Ther Sci 2019; 31:670-674. [PMID: 31528007 PMCID: PMC6698476 DOI: 10.1589/jpts.31.670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/28/2019] [Indexed: 12/05/2022] Open
Abstract
[Purpose] This study aimed to examine the impact of changing the drop vertical jump
stance time on kinematic and kinetic parameters by ordering to high jump or quick jump for
consistent stance time and a more accurate assessment of anterior cruciate ligament injury
risk. [Participants and Methods] The participants were 20 healthy female students. The
drop vertical jump was started by instructing the participants to stand on a 30-cm
platform with both legs stationary. The task was performed while the participants were
instructed to perform high jump or quick jump. [Results] Stance time was significantly
shorter with quick jump than with high jump. Quick jump showed significantly higher knee
abduction angles at initial contact and peak vertical ground reaction force, and lower hip
flexion, knee flexion, and ankle dorsiflexion angles at the lowest point of the center of
mass. Quick jump showed a significantly higher peak vertical ground reaction force. The
knee abduction moment at initial contact was not significantly different between the 2
conditions. [Conclusion] Quick jump was better than high jump for making stance time
consistent, and the differences in kinematic and kinetic characteristics by oral
instructions should be considered when using drop vertical jump.
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Affiliation(s)
- Hiroko Yokoyama
- Department of Comprehensive Rehabilitation Sciences, Hirosaki University Graduate School of Health Sciences: 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan
- Department of Rehabilitation, Hirosaki University Hospital, Japan
| | - Atsushi Oda
- Department of Health Sciences, Hirosaki University Graduate School of Health Sciences, Japan
| | - Misato Makino
- Department of Health Sciences, Hirosaki University Graduate School of Health Sciences, Japan
| | - Takaaki Ishikawa
- Department of Health Sciences, Hirosaki University Graduate School of Health Sciences, Japan
| | | | | | - Eiichi Tsuda
- Department of Rehabilitation Medicine, Hirosaki University Graduate School of Medicine, Japan
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25
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Armitano CN, Haegele JA, Russell DM. The Use of Augmented Information for Reducing Anterior Cruciate Ligament Injury Risk During Jump Landings: A Systematic Review. J Athl Train 2018; 53:844-859. [PMID: 30273010 DOI: 10.4085/1062-6050-320-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT: A comprehensive systematic review of the literature on the use of augmented information in anterior cruciate ligament (ACL) injury-prevention programs to improve jump-landing technique was conducted. The use of motor-learning concepts could provide more robust means of preventing ACL injuries. OBJECTIVE: To systematically summarize the effectiveness of augmented information in improving the biomechanical factors associated with an increased risk for ACL injury. DATA SOURCES: Articles were retrieved using the electronic databases of PubMed, MEDLINE, CINAHL, and Google Scholar and 3 lines of truncated search words: (a) lower extremity, knee, ACL, and anterior cruciate ligament; (b) prevention, injury prevention, and prehab; and (c) augmented information, augmented feedback, feedback, cue, and instruction. We also performed a hand search of the reference lists of the screened articles. DATA EXTRACTION: We independently assessed the methodologic quality using the Cochrane Group on Screening and Diagnostic Test Methods list. Articles were placed in 1 of 3 augmented-information categories: prescriptive, feedback, or transition. Articles were also categorized based on whether the information likely encouraged an internal or external focus of attention. DATA SYNTHESIS: The searches identified a total of 353 studies, of which 18 were included. Most researchers found that augmented information could lead to technique changes to reduce the biomechanical risk factors associated with ACL injury. The average methodologic quality of the studies was 11.8 out of 17, with a range from 8 to 15. The authors of only 7 studies examined retention of the improved techniques. CONCLUSIONS: The evidence suggests that augmented information can be used to significantly improve the biomechanical indicators associated with ACL injury and to enhance current ACL injury-prevention programs. Combined prescriptive and feedback information that encouraged both internal and external foci led to the largest retention effect sizes.
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Affiliation(s)
- Cortney N Armitano
- School of Physical Therapy & Athletic Training, Old Dominion University, Norfolk, VA
| | - Justin A Haegele
- Department of Human Movement Sciences, Old Dominion University, Norfolk, VA
| | - Daniel M Russell
- School of Physical Therapy & Athletic Training, Old Dominion University, Norfolk, VA
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Knee Frontal Plane Projection Angle: A Comparison Study Between Drop Vertical Jump and Step-Down Tests With Young Volleyball Athletes. J Sport Rehabil 2018; 28:153-158. [PMID: 29091512 DOI: 10.1123/jsr.2017-0204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
STUDY DESIGN Observational study. CONTEXT Altered frontal plane knee mechanics during dynamic tasks have been often associated with lower-extremity injuries. Strategies to decrease these risk factors and improve knee joint stability are often applied in rehabilitation and training environments. OBJECTIVE The purpose of this study was to compare knee joint frontal plane projection angles (FPPA) via 2-dimensional video analysis during drop vertical jump (DVJ) and step-down test (SDT) tasks in the preferred and nonpreferred limbs of young male and female volleyball players. METHODS A total of 60 young male (n = 29) and female (n = 31) volleyball players (13.6 [1.1] y, 62.2 [11.2] kg, and 170.8 [10] cm) participated in this study. Once the athletes were screened for inclusion and exclusion criteria, limb preference was operationally defined as the preferred kicking leg or the foot used for stair climbing. In a randomized study design, participants were asked to perform a bilateral DVJ and unilateral step-down landing tasks for both preferred and nonpreferred limb. Kinematic analysis was performed via a 2-dimensional video recording of knee joint FPPA alignment. RESULTS No difference was noted in FFPA during DVJ and SDT tasks between preferred and nonpreferred limbs in both male and female groups (P > .05). The FFPA was significantly higher for both limbs during DVJ versus SDT in both groups (P ≤ .05), but it was not different between male and female athletes. CONCLUSIONS Based on these findings, clinicians may expect young male and female volleyball athletes to demonstrate similar and symmetrical lower-extremity 2-dimensional knee joint FPPA values across screening tests intended to identify lower-extremity injury risk factors. However, greater FPPA values should be expected during the more dynamic DVJ task.
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Bourgeois FA, Gamble P, Gill ND, McGuigan MR. The Relationship Between Multidirectional Jumping and Performance in Change of Direction Tasks. J Strength Cond Res 2018; 32:690-699. [PMID: 29466271 DOI: 10.1519/jsc.0000000000002359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bourgeois, FA II, Gamble, P, Gill, ND, and McGuigan, MR. The relationship between multidirectional jumping and performance in change of direction tasks. J Strength Cond Res 32(3): 690-699, 2018-This study investigated the test-retest reliability of 2 change of direction (COD; 180 and 45° COD) sprints and 3 multidirectional jump (MDJ) tests. Variables examined were approach time (sprint before plant-step), exit time (sprint after plant-step), total time (time to completion) and MDJ approach time, and distance, respectively. Second, the ability of MDJ tests to predict performance in COD tests was examined. Twenty men (age: 27.5 ± 5.9 years; height: 1.79 ± 0.1 m; and body mass: 79.1 ± 12.0 kg) performed 5 trials for each assessment, executing left plant-leg (LT) and right plant-leg (RT) steps, on 2 testing occasions separated by 7 days. Between-session and within-session intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) for all measurements were calculated. Usefulness of COD and MDJ tests was assessed using typical error and smallest worthwhile change (SWC) comparison. Results showed only one MDJ measurement generated unstable between-session reliability. Within-session reliability of approach and exit COD times, and MDJ approach times possessed confidence limits (90% CL) that extended below 0.75 ICC. All COD total times and MDJ distances presented high reliability (ICC = 0.87-0.99) with low CV (0.9-4.1%). Right-leg MDJ distances were predictors of RT COD performances (r = 0.50-0.68, p = 0.001-0.024), whereas LT MDJ distances were predictors of LT180 COD performance (r = 0.67-0.71, p = 0.001). All measurements were useful in detecting SWC in performance. These findings suggest the COD tests and MDJ distances are reliable for assessing and monitoring COD performance in similar cohorts.
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Affiliation(s)
- Frank A Bourgeois
- Sports Performance Research Institute New Zealand, Auckland, New Zealand
| | - Paul Gamble
- Sports Performance Research Institute New Zealand, Auckland, New Zealand
| | - Nic D Gill
- Sports Performance Research Institute New Zealand, Auckland, New Zealand.,New Zealand Rugby Union, Wellington, New Zealand
| | - Mike R McGuigan
- Sports Performance Research Institute New Zealand, Auckland, New Zealand.,Edith Cowan University, Perth, Australia
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28
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Pedley JS, Lloyd RS, Read P, Moore IS, Oliver JL. Drop Jump: A Technical Model for Scientific Application. Strength Cond J 2017. [DOI: 10.1519/ssc.0000000000000331] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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29
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Struzik A, Juras G, Pietraszewski B, Rokita A. Effect of drop jump technique on the reactive strength index. J Hum Kinet 2016; 52:157-164. [PMID: 28149403 PMCID: PMC5260527 DOI: 10.1515/hukin-2016-0003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2016] [Indexed: 11/15/2022] Open
Abstract
The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05) between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05) than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05) than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.
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Affiliation(s)
- Artur Struzik
- Department of Team Sport Games, University School of Physical Education, Wroclaw, Poland
| | - Grzegorz Juras
- Department of Motor Behavior, Academy of Physical Education, Katowice, Poland
| | - Bogdan Pietraszewski
- Department of Biomechanics, University School of Physical Education, Wroclaw, Poland
| | - Andrzej Rokita
- Department of Team Sport Games, University School of Physical Education, Wroclaw, Poland
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