scholarly journals Effects of Two Competitive Soccer Matches on Landing Biomechanics in Female Division I Soccer Players

Sports ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 237
Author(s):  
Benjamin J. Snyder ◽  
Randolph E. Hutchison ◽  
Christopher J. Mills ◽  
Stephen J. Parsons
Keyword(s):  
Shear Force ◽  
Reaction Force ◽  
Knee Extension ◽  
Soccer Players ◽  
Control Group ◽  
Initial Contact ◽  
Time Points ◽  
Landing Biomechanics ◽  
Isometric Knee Extension ◽  
Before And After

Fatigue has been proposed to increase the risk of knee injury. This study tracked countermovement jump, knee isometric strength, and kinetics and kinematics in 8 female soccer players (experimental group) during an anticipated sidestep maneuver before and after two matches played over a 43-h period. Time points were: Before and after match 1 (T0 and T1), 12 h after the first match (T2), and immediately after the second match (T3). A control group participated only in practice sessions. Isometric knee extension strength decreased by 14.8% at T2 (p = 0.003), but knee flexion was not affected until T3, declining by 12.6% (p = 0.018). During the sidestep maneuver, knee joint degrees of flexion at initial contact was increased by 17.1% at T3, but maximum knee and hip angle at initial contact were unchanged. Peak resultant ground reaction force (GRF) increased by 12.6% (p = 0.047) at T3 (3.03 xBW) from 2.69 xBW at T0, while posterior GRF was significantly higher than T0 at all three subsequent time points (T1 = 0.82 ± 0.23 xBW, T2 = 0.87 ± 0.22 xBW, T3 = 0.89 ± 0.22 xBW). Anterior tibial shear force increased significantly (p = 0.020) at T3 (1.24 ± 0.12 xBW) compared to T1 (1.15 ± 0.13 xBW), an 8.8% increase. Lateral tibial shear force was significantly higher at both T1 (0.95 ± 0.20 xBW) and T3 (1.15 ± 0.38 xBW) compared to T0 (0.67 ± 0.25 xBW). These findings suggest that participation in a soccer match has significant effects on both physical performance parameters and kinetics/kinematics during a sidestep cut, but these can be more pronounced after a second match with short rest.

Landing Evaluation in Soccer Players with or without Anterior Cruciate Ligament Reconstruction

2020 ◽  
Vol 41 (13) ◽  
pp. 962-971
Author(s):  
Ahmad Alanazi ◽  
Katy Mitchell ◽  
Toni Roddey ◽  
Aqeel Alenazi ◽  
Msaad Alzhrani ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Cruciate Ligament ◽  
Knee Extension ◽  
Soccer Players ◽  
Control Group ◽  
Landing Biomechanics ◽  
Healthy Control ◽  
Anterior Cruciate ◽  
Hip Flexion ◽  
Main Effects

AbstractThe purpose of this study was to evaluate landing biomechanics in soccer players following ACLR during two landing tasks. Eighteen soccer players with an ACLR and 18 sex-matched healthy control soccer players participated in the study. Planned landing included jumping forward and landing on the force-plates, whereas unplanned landing included jumping forward to head a soccer ball and landing on the force-plates. A significant landing×group interaction was found only for knee flexion angles (p=0.002). Follow-up comparisons showed that the ACL group landed with greater knee flexion during planned landing compared with unplanned landing (p<0.001). Significant main effects of landing were found. The unplanned landing showed reduction in hip flexion (p<0.001), hip extension moments (p<0.013), knee extension moments (p<0.001), and peak pressure (p<0.001). A significant main effect for group for gastrocnemius muscle was found showing that the ACL group landed with reduced gastrocnemius activity (p=0.002). Unplanned landing showed greater injury predisposing factors compared with planned landing. The ACL group showed nearly similar landing biomechanics to the control group during both landing tasks. However, the ACL group used a protective landing strategy by reducing gastrocnemius activity.

scholarly journals Effectiveness of hamstring stretching using a pressure biofeedback unit for 4 weeks: A randomized controlled trial

2020 ◽  
Vol 40 (02) ◽  
pp. 99-107
Author(s):  
Jin-Oh Ahn ◽  
Jong-Hyuck Weon ◽  
Eun-Kyung Koh ◽  
Do-Young Jung
Keyword(s):  
Controlled Trial ◽  
Intervention Group ◽  
Knee Extension ◽  
Control Group ◽  
Post Intervention ◽  
Lower Back ◽  
Hamstring Muscles ◽  
Before And After ◽  
The Difference ◽  
Pressure Biofeedback

Background: Stretching and length test of hamstring muscles have been performed commonly to manage lower back pain (LBP) in sports rehabilitation. Previous literatures addressed that stretching techniques and length test of hamstring muscles should be performed with the pelvic maintained in an anterior tilt position. However, there is no study to determine the effectiveness of pressure biofeedback unit (PBU) to maintain in anterior pelvic tilting (APT) on length test and stretching of hamstring muscles. Objective: To determine the effectiveness of hamstring muscles stretching using a PBU. Methods: Forty participants with shortness of hamstrings randomized into two groups. Participants performed the active knee extension (AKE) stretching without (control group) or with PBU (intervention group) for four weeks. AKE tests without and with PBU were administered three times before and after hamstrings stretching by each group. Results: The AKE test without PBU showed a significant main effect of time ([Formula: see text]) but not of group ([Formula: see text]) on the AKE angle. The AKE test with PBU showed a significant increase in the AKE angle in the post-intervention compared to the pre-intervention assessments in both groups ([Formula: see text]). The difference of AKE angle between the pre- and post-intervention results was significantly greater in the intervention group than in the control group ([Formula: see text]). Conclusion: We recommend the use of a PBU to maintain the pelvic anterior tilting position when performing the AKE test or AKE stretching.

Quadriceps and Hamstrings Fatigue Alters Hip and Knee Mechanics

2010 ◽  
Vol 26 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Abbey C. Thomas ◽  
Scott G. McLean ◽  
Riann M. Palmieri-Smith
Keyword(s):  
Repeated Measures ◽  
Injury Risk ◽  
Mixed Model ◽  
External Rotation ◽  
Reaction Force ◽  
Acl Injury ◽  
Knee Extension ◽  
Initial Contact ◽  
Knee Mechanics ◽  
Acl Injury Risk

Neuromuscular fatigue exacerbates abnormal landing strategies, which may increase noncontact anterior cruciate ligament (ACL) injury risk. The synergistic actions of quadriceps and hamstrings (QH) muscles are central to an upright landing posture, though the precise effect of simultaneous fatigue of these muscles on landing and ACL injury risk is unclear. Elucidating neuromechanical responses to QH fatigue thus appears important in developing more targeted fatigue-resistance intervention strategies. The current study thus aimed to examine the effects of QH fatigue on lower extremity neuromechanics during dynamic activity. Twenty-five healthy male and female volunteers performed three single-leg forward hops onto a force platform before and after QH fatigue. Fatigue was induced through sets of alternating QH concentric contractions, on an isokinetic dynamometer, until the first five repetitions of a set were performed at least 50% below QH peak torque. Three-dimensional hip and knee kinematics and normalized (body mass × height) kinetic variables were quantified for pre- and postfatigue landings and subsequently analyzed by way of repeated- measures mixed-model ANOVAs. QH fatigue produced significant increases in initial contact (IC) hip internal rotation and knee extension and external rotation angles (p< .05), with the increases in knee extension and external rotation being maintained at the time of peak vertical ground reaction force (vGRF) (p< .05). Larger knee extension and smaller knee fexion and external rotation moments were also evident at peak vGRF following fatigue (p< .05). Females landed with greater hip fexion and less abduction than males at both IC and peak vGRF as well as greater knee fexion at peak vGRF (p< .05). The peak vGRF was larger for females than males (p< .05). No sex × fatigue effects were found (p> .05). Fatigue of the QH muscles altered hip and knee neuromechanics, which may increase the risk of ACL injury. Prevention programs should incorporate methods aimed at countering QH fatigue.

scholarly journals Disparate kinetics of change in responses to electrical stimulation at the thoracic and lumbar level during fatiguing isometric knee extension

2020 ◽  
Vol 128 (1) ◽  
pp. 159-167 ◽  
Author(s):  
Callum G. Brownstein ◽  
Robin Souron ◽  
Nicolas Royer ◽  
Benjamin Singh ◽  
Thomas Lapole ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Evoked Potential ◽  
Isometric Exercise ◽  
Silent Period ◽  
Knee Extension ◽  
Lower Limbs ◽  
Evoked Responses ◽  
Time Points ◽  
Isometric Knee Extension ◽  
Kinetics Of

The present study compared the fatigue-induced change of matched-amplitude thoracic evoked potential (TMEP) and lumbar evoked potential (LEP) following electrical stimulation. Ten participants performed a 3 × 3 min isometric knee extension contraction separated by 4 min of recovery at the level of EMG required to produce 50% maximal voluntary contraction (MVC) force at baseline. The TMEP and LEP were evoked during the ongoing contraction at baseline and every minute into the fatiguing protocol and during recovery. Both responses were also assessed during a transcranial magnetic stimulation (TMS) evoked silent period to elicit a TMS-TMEP and TMS-LEP to assess responses without the confounding influence of descending drive. The results displayed disparate kinetics of the TMS-TMEP and TMS-LEP throughout the fatiguing protocol. The TMS-TMEP was reduced at all time points during exercise ( P < 0.001), whereas the TMS-LEP was reduced at 2 min into set 1 and 1 min into sets 2 and 3 ( P ≤ 0.04). TMS-LEPs were higher than the TMS-TMEPs at most time points ( P ≤ 0.04). No change was observed in the TMEP or LEP. When evoked during the silent period, the reduction in TMEP is greater than the LEP during fatiguing isometric exercise. The disparate kinetics of change suggest that differential mechanisms are responsible for evoked responses to thoracic and lumbar stimulation. More research is required to identify the mechanisms responsible for the TMEP and LEP before precise inferences can be made on what fatigue-induced changes in these variables reflect. NEW & NOTEWORTHY Assessing spinal excitability using lumbar stimulation when measuring responses in lower limbs has been suggested as an alternative method that could circumvent the issues associated with thoracic stimulation. The present study compared responses to the two types of stimuli throughout a fatiguing protocol and demonstrated that lumbar evoked responses differ substantially from thoracic responses when measured in the absence of voluntary drive. These findings suggest that different mechanisms are responsible for evoked responses to thoracic and lumbar stimuli.

scholarly journals Effect of Core Training on Trunk Flexor Musculature in Male Soccer Players

2017 ◽  
Vol 1 (04) ◽  
pp. E147-E154 ◽  
Author(s):  
Yohei Takai ◽  
Miyuki Nakatani ◽  
Takuya Akamine ◽  
Katsuyuki Shiokawa ◽  
Daisuke Komori ◽  
...  
Keyword(s):  
Body Mass ◽  
Training Group ◽  
Soccer Players ◽  
Whole Body ◽  
Control Group ◽  
Training Groups ◽  
Trunk Segment ◽  
Before And After ◽  
Core Training ◽  
Training Modalities

AbstractThe present study aimed to elucidate the effect of core training on trunk flexor musculature in athletes. Twenty-eight collegiate male soccer players were randomly assigned to three groups: a training group that performed core exercises with wheeled platforms (WP), a training group that performed body mass-based core exercise (BME), and a control group that did not perform core exercise training (CON). WP and BME trained twice a week for 10 weeks. The WP performed 8–14 exercises with wheeled platforms. BME conducted four core exercises to failure. Before and after the intervention, trunk segment lean body mass (LBM) was measured using a whole-body dual-energy X-ray absorptiometry scanner. Muscle thicknesses (MTs) of the rectus abdominis (RA), external oblique, internal oblique (IO), and transverse abdominis were determined with an ultrasound apparatus. No significant changes for any measured variables were found in CON. In both training groups, the trunk segment LBM was significantly increased through the intervention. While MT for IO significantly increased in the two training groups, significant increases in MT for RA were found in only WP. For collegiate soccer players, the core training programs adopted here can be effective in increasing trunk segment LBM, but the effectiveness on the trunk flexor muscularity differs between the two training modalities.

scholarly journals Lengthening the Hamstring Muscles Without Stretching Using “Awareness Through Movement”

2006 ◽  
Vol 86 (12) ◽  
pp. 1641-1650 ◽  
Author(s):  
James Stephens ◽  
Joshua Davidson ◽  
Joseph DeRosa ◽  
Michael Kriz ◽  
Nicole Saltzman
Keyword(s):  
Muscle Length ◽  
Knee Extension ◽  
Control Group ◽  
Active Movement ◽  
Hamstring Muscle ◽  
Screening Criteria ◽  
Passive Stretching ◽  
Hamstring Muscles ◽  
Before And After ◽  
And Control

Abstract Background and PurposePassive stretching is widely used to increase muscle flexibility, but it has been shown that this process does not produce long-term changes in the viscoelastic properties of muscle as originally thought. The authors tested a method of lengthening hamstring muscles called “Awareness Through Movement” (ATM) that does not use passive stretching. Subjects. Thirty-three subjects who were randomly assigned to ATM and control groups met the screening criteria and completed the intervention phase of the study. Methods. The ATM group went through a process of learning complex active movements designed to increase length in the hamstring muscles. Hamstring muscle length was measured before and after intervention using the Active Knee Extension Test. Results. The ATM group gained significantly more hamstring muscle length (+7.04°) compared with the control group (+1.15°). Discussion and Conclusions. The results suggest that muscle length can be increased through a process of active movement that does not involve stretching. Further research is needed to investigate this finding.

scholarly journals Intravenous thrombolysis in combination with mild hypothermia therapy in the treatment of acute cerebral infarction

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Xiaoying Liu ◽  
Shengli Rao ◽  
Jiajia Wang
Keyword(s):  
Cerebral Infarction ◽  
Conventional Treatment ◽  
Mild Hypothermia ◽  
Intravenous Thrombolysis ◽  
Acute Cerebral Infarction ◽  
Control Group ◽  
Observation Group ◽  
Nihss Score ◽  
Time Points ◽  
Before And After

Objective: To investigate the efficacy of recombinant tissue plasminogen activator (rt-PA) intravenous thrombolysis in combination with mild hypothermia therapy in the treatment of acute cerebral infarction. Methods: One hundred and thirty-two patients with acute cerebral infarction who were admitted to our hospital were selected and grouped into a control group and an observation group, 66 each group. Patients in the control group were given conventional treatment in combination with local mild hypothermia therapy, and patients in the observation group were given rt-PA intravenous thrombolysis on the basis of conventional treatment and local mild hypothermia therapy. National institute of health stroke scale (NIHSS) score and intracranial pressure (ICP) of the two groups before and after treatment was recorded. The efficacy of the two groups was evaluated. The modified Rankin scale (MRS) score was followed up for three months. The blood samples of the patients were collected before and after thrombolysis. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels in the plasma were detected. Results: The NIHSS score of the two groups decreased in the 1st, 3rd and 7th day after treatment compared to before treatment (p<0.05), but the NIHSS score of the two groups had no significant difference at different time points after treatment (p>0.05). The ICP of the two groups decreased in the 1st, 3rd and 7th day after treatment compared to before treatment (p<0.05), and the decrease of ICP of the observation group was more significant than that of the control group at the same time point (1st, 3rd and 7th day after treatment) (p<0.05). The clinical efficacy of the observation group was higher than that of the control group after treatment, and the difference was statistically significant (p<0.05). The MDA concentration of both groups decreased at different time points after treatment (p<0.05), but the SOD concentration increased (p<0.05). The MDA concentration of the observation group was lower than that of the control group at different time points after treatment (p<0.05), and the SOD concentration of the observation group was higher than that of the control group (p<0.05). Conclusion: rt-PA intravenous thrombolysis in combination with mild hypothermia therapy has significant efficacy in the treatment of acute cerebral infarction. It can effectively relieve neurological function. Its action mechanism may be realized by relieving oxidative stress response. doi: https://doi.org/10.12669/pjms.35.4.311 How to cite this:Liu X, Rao S, Wang J. Intravenous thrombolysis in combination with mild hypothermia therapy in the treatment of acute cerebral infarction. Pak J Med Sci. 2019;35(4):1161-1166. doi: https://doi.org/10.12669/pjms.35.4.311 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals Efectos a corto plazo de un programa de entrenamiento de sobrecarga excéntrica sobre el rendimiento físico en jugadores de fútbol de élite U-16 (Short-term effects of an eccentric-overload training program on the physical performance on U-16 elite soccer

Retos ◽  
2017 ◽  
pp. 106-111
Author(s):  
Javier Raya-González ◽  
Luis Suárez-Arrones ◽  
Antonio Rísquez Bretones ◽  
Eduardo Sáez de Villarreal
Keyword(s):  
Training Program ◽  
Peak Power ◽  
Soccer Players ◽  
Control Group ◽  
Mean Power ◽  
Overload Training ◽  
Squat Exercise ◽  
Before And After ◽  
Soccer Training ◽  
Eccentric Overload

Resumen. El objetivo de este trabajo fue analizar el efecto de un programa de entrenamiento de fuerza con sobrecarga excéntrica (squat lateral ejecutado en un dispositivo inercial) sobre el rendimiento en futbolistas junior de élite. Dieciséis futbolistas de 14.7 ± .2 años de edad fueron asignados aleatoriamente en dos grupos: grupo control (n=8, GC) y grupo de fuerza (n=8, GF). El GF complementó su entrenamiento habitual de fútbol con el programa específico de fuerza con sobrecarga excéntrica propuesto dos días a la semana durante 6 semanas. Antes y después del periodo de intervención se midió la altura de salto vertical, el tiempo de sprint lineal y con cambio de dirección (COD) y la potencia del tren inferior. Se obtuvieron mejoras sustanciales (probables a muy probables) en GF en el salto con contramovimiento (CMJ) (TE: .46), en el porcentaje de pérdida de COD-Izquierda (TE: 1.39) y en la potencia media (TE: .73) y potencia máxima (TE: .65). El análisis inter-grupos mostró mejoras sustanciales mayores en GF respecto a GC en CMJ (TE: .79), en el porcentaje de pérdida de COD-Derecha (TE: 1.14), en la potencia media (TE: 1.04) y en la potencia máxima (TE: .88). Los resultados obtenidos sugieren que incluir un programa de entrenamiento de fuerza con sobrecarga excéntrica en la programación del entrenamiento de fútbol permite optimizar la condición física específica del futbolista.Palabras clave. Salto vertical, potencia máxima, capacidad de sprintar, cambio de dirección, fútbol. Abstract. To analyse the effect of an eccentric-overload training program (i.e., lateral squat exercise using a flywheel device) on performance in junior elite soccer players. Sixteen soccer players (14.7 ± .2 years) were randomly assigned to 2 groups: control group (n=8, CG) and strength group (n=8, SG). The SG complemented soccer training with a proposed eccentric-overload training program 2 days per weeks during 6 weeks. Before and after the training period jumping ability, linear and non-linear sprint and lower-limb power were measured. Substantial improvements (likely to very likely) were found in the SG in CMJ (ES: .46), percent decrement of COD-L (ES: 1.39) and Mean Power (ES: .73) and Peak Power (ES: .65). Between-groups analysis showed greater substantial improvements in SG in relation to CG in CMJ (ES: .79), percent decrement of COD-R (ES: 1.14) and Mean Power (ES: 1.04) and Peak Power (ES: .88). These results suggest that the inclusion of an eccentric-overload training program in soccer training periodization allow the optimization of the specific physical condition of soccer players.

Very-Heavy Sled Training for Improving Horizontal-Force Output in Soccer Players

2017 ◽  
Vol 12 (6) ◽  
pp. 840-844 ◽  
Author(s):  
Jean-Benoît Morin ◽  
George Petrakos ◽  
Pedro Jiménez-Reyes ◽  
Scott R. Brown ◽  
Pierre Samozino ◽  
...  
Keyword(s):  
Body Mass ◽  
Effect Size ◽  
Reaction Force ◽  
Force Production ◽  
Sprint Performance ◽  
Soccer Players ◽  
Control Group ◽  
Horizontal Force ◽  
Sprint Training ◽  
Practical Applications

Background:Sprint running acceleration is a key feature of physical performance in team sports, and recent literature shows that the ability to generate large magnitudes of horizontal ground-reaction force and mechanical effectiveness of force application are paramount. The authors tested the hypothesis that very-heavy loaded sled sprint training would induce an improvement in horizontal-force production, via an increased effectiveness of application.Methods:Training-induced changes in sprint performance and mechanical outputs were computed using a field method based on velocity–time data, before and after an 8-wk protocol (16 sessions of 10- × 20-m sprints). Sixteen male amateur soccer players were assigned to either a very-heavy sled (80% body mass sled load) or a control group (unresisted sprints).Results:The main outcome of this pilot study is that very-heavy sled-resisted sprint training, using much greater loads than traditionally recommended, clearly increased maximal horizontal-force production compared with standard unloaded sprint training (effect size of 0.80 vs 0.20 for controls, unclear between-groups difference) and mechanical effectiveness (ie, more horizontally applied force; effect size of 0.95 vs –0.11, moderate between-groups difference). In addition, 5-m and 20-m sprint performance improvements were moderate and small for the very-heavy sled group and small and trivial for the control group, respectively.Practical Applications:This brief report highlights the usefulness of very-heavy sled (80% body mass) training, which may suggest value for practical improvement of mechanical effectiveness and maximal horizontal-force capabilities in soccer players and other team-sport athletes.Results:This study may encourage further research to confirm the usefulness of very-heavy sled in this context.

Laboratory Gait Analysis in Patients with Low Back Pain before and after a Pilates Intervention

2009 ◽  
Vol 18 (2) ◽  
pp. 269-282 ◽  
Author(s):  
Juliana Limba da Fonseca ◽  
Marcio Magini ◽  
Thais Helena de Freitas
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Outcome Measures ◽  
Lower Limb ◽  
Controlled Trial ◽  
Reaction Force ◽  
Control Group ◽  
Low Back ◽  
Before And After ◽  
Pilates Method

Objective:To evaluate the influence of pain on vertical ground-reaction force (VGRF) in patients with low back problems and the effect of the Pilates method on the gait of these patients.Design:A single-blind randomized controlled trial.Participants:28 individuals assigned to a control group (n = 11) and a low-back group (n = 17), the latter of which was subdivided into a Pilates group (n = 8) and a no-Pilates group (n = 9).Intervention:The Pilates group undertook 15 sessions of Pilates.Main Outcome Measures:The VGRF parameters were recorded during preferred and faster walking speeds. The data were collected before and after the intervention.Results:The weight-acceptance rate and push-off rate were significantly less in the right lower limb of low-back group than of the control group at preferred speed. Improvements were seen in the Pilates group postintervention, with increased middle-support force for the left lower limb at faster walking speed and decreased pain; this did not occur in the no-Pilates group.Conclusions:These results suggest that patients with low back pain use strategies to attenuate the amount of force imposed on their body. The Pilates method can improve weight discharge in gait and reduce pain compared with no intervention.

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