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Eccentric strength

Stephen P Bird, William J Markwick
BACKGROUND AND PURPOSE: Youth participation in basketball is on the rise, with basketball one of the top five participation sports in Australia. With increased participation there is a need for greater awareness of the importance of the pre-participation examination, including musculoskeletal screening and functional performance testing as part of a multidisciplinary approach to reducing the risk for future injuries. As majority of all basketball injuries affect the lower extremities, pre-participation musculoskeletal screening and functional performance testing should assess fundamental movement qualities throughout the kinetic chain with an emphasis on lower extremity force characteristics, specifically eccentric loading tasks...
October 2016: International Journal of Sports Physical Therapy
Wesam Saleh A Al Attar, Najeebullah Soomro, Peter J Sinclair, Evangelos Pappas, Ross H Sanders
BACKGROUND: Hamstring injuries are among the most common non-contact injuries in sports. The Nordic hamstring (NH) exercise has been shown to decrease risk by increasing eccentric hamstring strength. OBJECTIVE: The purpose of this systematic review and meta-analysis was to investigate the effectiveness of the injury prevention programs that included the NH exercise on reducing hamstring injury rates while factoring in athlete workload. METHODS: Two researchers independently searched for eligible studies using the following databases: the Cochrane Central Register of Controlled Trials via OvidSP, AMED (Allied and Complementary Medicine) via OvidSP, EMBASE, PubMed, MEDLINE, SPORTDiscus, Web of Science, CINAHL and AusSportMed, from inception to December 2015...
October 17, 2016: Sports Medicine
Pavlos E Evangelidis, Garry J Massey, Richard A Ferguson, Patrick C Wheeler, Matthew T G Pain, Jonathan P Folland
Hamstrings muscle fiber composition may be predominantly fast-twitch and could explain the high incidence of hamstrings strain injuries. However, hamstrings muscle composition in vivo, and its influence on knee flexor muscle function, remains unknown. We investigated biceps femoris long head (BFlh) myosin heavy chain (MHC) composition from biopsy samples, and the association of hamstrings composition and hamstrings muscle volume (using MRI) with knee flexor maximal and explosive strength. Thirty-one young men performed maximal (concentric, eccentric, isometric) and explosive (isometric) contractions...
October 13, 2016: Scandinavian Journal of Medicine & Science in Sports
Joel Pearson, Rocco Chiou, Sebastian Rogers, Marcus Wicken, Stewart Heitmann, Bard Ermentrout
Hallucinations occur in both normal and clinical populations. Due to their unpredictability and complexity, the mechanisms underlying hallucinations remain largely untested. Here we show that visual hallucinations can be induced in the normal population by visual flicker, limited to an annulus that constricts content complexity to simple moving grey blobs, allowing objective mechanistic investigation. Hallucination strength peaked at ~11 Hz flicker and was dependent on cortical processing. Hallucinated motion speed increased with flicker rate, when mapped onto visual cortex it was independent of eccentricity, underwent local sensory adaptation and showed the same bistable and mnemonic dynamics as sensory perception...
October 11, 2016: ELife
Paige E Rice, Courtney L Goodman, Christopher R Capps, N Travis Triplett, Travis M Erickson, Jeffrey M McBride
The purpose of this study was to compare force- and power-time curve variables during jumping between Division I strength-matched male and female basketball athletes. Males (n = 8) and females (n = 8) were strength matched by testing a one-repetition maximum (1RM) back squat. 1RM back squat values were normalised to body mass in order to demonstrate that strength differences were a function of body mass alone. Subjects performed three countermovement jumps (CMJ) at maximal effort. Absolute and relative force- and power-time curve variables from the CMJs were analysed between males and females...
October 1, 2016: European Journal of Sport Science
Pascal Edouard, Pierrick Arnal, Philippe Gimenez, Pierre Samozino, Pedro Jimenez-Reyes, Matt Brughelli, Jurdan Mendiguchia, Jean-Benoit Morin
OBJECTIVE: The hamstring muscles are the most injured muscles in athletes practicing sprints. However, they seem greatly contributing to the production of horizontal force, a key element in the sprint acceleration performance. The aim of our study was to experimentally analyse the link between the production of horizontal force and strength of the hamstrings at maximum sprints on a treadmill and in fatigue conditions. PATIENTS AND METHODS: Fourteen male subjects accustomed to sprint participated in the experiment consisting in 12 6-seconds sprints separated by 44seconds of recovery on an instrumented treadmill sprint for measuring the horizontal force, coupled with the simultaneous recording of the EMG activity of the vastus lateralis, rectus biceps femoris and gluteus muscles...
September 2016: Annals of Physical and Rehabilitation Medicine
Alexandre Rambaud, Bertrand Semay, Jean-Benoit Morin, Rémi Phillipot, Pierre Samozino, Pascal Edouard
OBJECTIVE: A criterion of the anterior cruciate ligament reconstruction (ACLR) success is the return to sport at the same level as before surgery. Return to sport (RtS) decision seems to be a key element in this success: if too early RtS exposes to risk of injury, too late RtS influences the motivation to return to the same level. Functional tests (Hop Tests) and isokinetic assessments (Isok Tests) are usually performed to guide this decision. However, a precise and objective biomechanical analysis of running pattern would be more similarly to the sport activity...
September 2016: Annals of Physical and Rehabilitation Medicine
Karima Belhaj, Soumia Meftah, Siham Zahi, Fatima Lmidmani, Abdellatif Elfatimi
OBJECTIVE: Isokinetic evaluation allows accurate and reproducible measurement of dynamic muscle strength. It has several application areas, especially in sports, it allows the evaluation, rehabilitation and re-entrainment. It is rarely used for the hip joint. The objective of this study was to report the isokinetic profile of the abductor and adductor muscles of the hip in Moroccan professional players, while comparing players with a history of groin for those without medical history at the hip...
September 2016: Annals of Physical and Rehabilitation Medicine
Laila Mahir, Karima Belhaj, Siham Zahi, Fatima Lmidmani, Abdellatif El Fatimi
OBJECTIVE: The isokinetic is a means of objective and reproducible assessment of muscle strength, it is widely used in rehabilitation especially joint and muscle pathology. There is little applied to the neurological disease. To report the experience of our rehabilitation field service isokinetic knee of hemiplegic through three observations. OBSERVATIONS: Observation 1: 65 years old patient, who suffered an ischemic stroke right for 2 years, who presented a quadriceps spasticity 2, walking with a cane, he received isokinetic knee rehabilitation for a year, with exercises concentric, eccentric and proprioceptive...
September 2016: Annals of Physical and Rehabilitation Medicine
Lee A Bridgeman, Michael R McGuigan, Nicholas D Gill, Deborah Dulson
The aims of this study were to (A) investigate the acute effects of different drop jump (DJ) accentuated eccentric loading (AEL) protocols and (B) to investigate the effect of these AEL DJ protocols on subsequent countermovement jump (CMJ) performance. The subjects were 12 strength-trained athletes, initially, baseline CMJ performance was assessed and individual optimal DJ drop height identified. In subsequent weeks subjects completed 1 set of 5 DJ's with no additional load or an AEL of 10, 20 or 30% of their individual body mass (BM) utilising dumbbells to provide the extra load...
September 16, 2016: Journal of Strength and Conditioning Research
Jamie Douglas, Simon Pearson, Angus Ross, Mike McGuigan
BACKGROUND: Resistance training is an integral component of physical preparation for athletes. A growing body of evidence indicates that eccentric strength training methods induce novel stimuli for neuromuscular adaptations. OBJECTIVE: The purpose of this systematic review was to determine the effects of eccentric training in comparison to concentric-only or traditional (i.e. constrained by concentric strength) resistance training. METHODS: Searches were performed using the electronic databases MEDLINE via EBSCO, PubMed and SPORTDiscus via EBSCO...
September 19, 2016: Sports Medicine
Taegyu Kim, Eunkuk Kim, Hokyung Choi
OBJECTIVE: To determine whether a neuromuscular rehabilitation program can improve postural stability, and ankle evertor strength, and to examine the temporal changes and persistence of the rehabilitation effects in athletes with chronic ankle instability (CAI). DESIGN: A total of 21 national women's field hockey players participated in this study (CAI, n = 12; control, n = 9). Main outcome measures included isokinetic ankle evertor strength (peak torque, PT; total work, TW) at 30°/s, 60°/s, 90°/s and 120°/s, mediolateral stability index (MSI), and dynamic stability test (TCT)...
August 24, 2016: Journal of Sport Rehabilitation
Kathleen A Swanik, Stephen J Thomas, Aaron H Struminger, Kellie C Huxel Bliven, John D Kelly Iv, Charles B Swanik
CONTEXT: Plyometric training is credited with providing benefits in performance and dynamic restraint. However, limited prospective data exists quantifying kinematic adaptations such as amortization time, glenohumeral rotation, and scapulothoracic position, which may underlie its efficacy for upper extremity rehabilitation or performance enhancement. OBJECTIVE: To measure upper extremity kinematics and plyometric phase times before and after an 8 week upper extremity strength and plyometric training programs...
August 24, 2016: Journal of Sport Rehabilitation
Katherine Lee, James Onate, Samar McCann, Tamerah Hunt, Wilbert Turner, Mark Merrick
Clinical Scenario: In wrestling, athletes often support a large amount of weight on their heads or are forced into extreme ranges of motion. These suboptimal movement conditions lead to a high prevalence of neck injuries in wrestlers. A large portion of the work done by the cervical musculature in wrestling is theorized to be eccentric or isometric types of contractions. Strengthening of these cervical muscles is clinically considered to play a vital role in being competitive on the wrestling mat. The cervical stability provided by strengthening these muscles may also play a part in injury prevention among wrestlers...
August 24, 2016: Journal of Sport Rehabilitation
Timothy F Tyler, Brandon M Schmitt, Stephen J Nicholas, Malachy McHugh
CONTEXT: Hamstring strain injuries have a high recurrence rate. OBJECTIVE: To determine if a protocol emphasizing eccentric strength training with the hamstrings in a lengthened position resulted in a low recurrence rate. DESIGN: Longitudinal cohort study Setting: Sports medicine physical therapy clinic. PARTICIPANTS: 50 athletes with hamstring strain injury (age 36±16 yo; 30 men, 20 women; 3 G1, 43 G2, 4 G3; 25 recurrent injuries) followed a 3-phase rehabilitation protocol emphasizing eccentric strengthening with the hamstrings in a lengthened position...
August 24, 2016: Journal of Sport Rehabilitation
Kris Beattie, Brian P Carson, Mark Lyons, Ian C Kenny
Maximum- and reactive-strength qualities both have important roles in athletic movements and sporting performance. Very little research has investigated the relationship between maximum-strength and reactive-strength. The aim of this study was to investigate the relationship between maximum-strength (isometric mid-thigh pull peak force; IMTP PF) and reactive-strength (drop-jump reactive-strength index; DJ-RSI) variables at 0.3 m, 0.4 m, 0.5 m and 0.6 m box heights. A secondary aim investigated the between- and within-group differences in reactive-strength characteristics between relatively 'strong' and 'weak' athletes...
September 6, 2016: International Journal of Sports Physiology and Performance
Roberto Monaco
Long Josephson tunnel junctions are non-linear transmission lines that allow propagation of current vortices (fluxons) and electromagnetic waves and are used in various applications within superconductive electronics. Recently, the Josephson vortex has been proposed as a new superconducting qubit. We describe a simple method to create a double-well potential for an individual fluxon trapped in a long elliptic annular Josephson tunnel junction characterized by an intrinsic non-uniform width. The distance between the potential wells and the height of the inter-well potential barrier are controlled by the strength of an in-plane magnetic field...
November 9, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Hamza Ozer, Hakan Y Selek, Gulcan Harput, Ali Oznur, Gul Baltaci
The aim of the present study was to investigate the outcomes after open repair of Achilles tendon rupture augmented with a distal turndown gastrocnemius flap and deep posterior crural fasciotomy based on the modified Lindholm technique. Twenty-three patients with acute Achilles tendon injury underwent open end-to-end tendon repair augmented with a distal turndown gastrocnemius flap and deep posterior compartment fasciotomy. The concentric and eccentric muscle strength was measured using a functional squat system, and dynamic balance was assessed using the Y-balance test with anterior, posteromedial, and posterolateral reach distances...
August 23, 2016: Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons
Norio Hotta, Kaoru Yamamoto, Hisayoshi Ogata, Patrick Maher, Naoya Okumura, Koji Ishida
Previous research has shown an exaggeration in exercise hyperpnea 2 days after eccentric exercise (ECC). Enhancement in central command has been suggested as one candidate to account for this effect given that ECC-induced neuromuscular dysfunction increases relative exercise intensity, thus resulting in reinforcement of effort sense. The purpose of this study was, therefore, to elucidate whether the degree of alteration in effort sense caused by ECC affects exercise hyperpnea. Ten subjects performed 20-s single-arm extension-flexion exercises with weight strapped to the wrist, and ventilatory response was measured before (Pre) and 2 days after ECC (D2)...
2016: Journal of Physiological Anthropology
K L Holt, D P Raper, C E Boettcher, G S Waddington, M K Drew
OBJECTIVES: To investigate inter and intra-rater reliability of hand held (HHD) and externally fixed (EFD) dynamometry for shoulder internal (IR) and external rotation (ER) strength and their correlation to isokinetic testing. DESIGN: Within participant, inter and intra-rater reliability study. PARTICIPANTS: Twenty active, healthy male and female participants underwent testing by two examiners. OUTCOME MEASURES: Intra-class coefficients (ICC), percentage standard error of measurement (%SEM), and percentage minimal detectable change (%MDC) were calculated for inter-rater, intra-day and intra-rater, inter-week reliability...
September 2016: Physical Therapy in Sport
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