scholarly journals Deceleration Training in Team Sports: Another Potential ‘Vaccine’ for Sports-Related Injury?

2021 ◽  
Author(s):  
Alistair J. McBurnie ◽  
Damian J. Harper ◽  
Paul A. Jones ◽  
Thomas Dos’Santos
Keyword(s):  
High Intensity ◽  
Reaction Force ◽  
Team Sports ◽  
New Developments ◽  
Change Of Direction ◽  
Force Profile ◽  
Potential Vaccine ◽  
Sprinting Speed ◽  
Opinion Article

AbstractHigh-intensity horizontal decelerations occur frequently in team sports and are typically performed to facilitate a reduction in momentum preceding a change of direction manoeuvre or following a sprinting action. The mechanical underpinnings of horizontal deceleration are unique compared to other high-intensity locomotive patterns (e.g., acceleration, maximal sprinting speed), and are characterised by a ground reaction force profile of high impact peaks and loading rates. The high mechanical loading conditions observed when performing rapid horizontal decelerations can lead to tissue damage and neuromuscular fatigue, which may diminish co-ordinative proficiency and an individual’s ability to skilfully dissipate braking loads. Furthermore, repetitive long-term deceleration loading cycles if not managed appropriately may propagate damage accumulation and offer an explanation for chronic aetiological consequences of the ‘mechanical fatigue failure’ phenomenon. Training strategies should look to enhance an athlete’s ability to skilfully dissipate braking loads, develop mechanically robust musculoskeletal structures, and ensure frequent high-intensity horizontal deceleration exposure in order to accustom individuals to the potentially damaging effects of intense decelerations that athletes will frequently perform in competition. Given the apparent importance of horizontal decelerations, in this Current Opinion article we provide considerations for sport science and medicine practitioners around the assessment, training and monitoring of horizontal deceleration. We feel these considerations could lead to new developments in injury-mitigation and physical development strategies in team sports.

scholarly journals Influence of Strength and Power Capacity on Change of Direction Speed and Deficit in Elite Team-Sport Athletes

2019 ◽  
Vol 68 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Tomás T. Freitas ◽  
Lucas A. Pereira ◽  
Pedro E. Alcaraz ◽  
Ademir F. S. Arruda ◽  
Aristide Guerriero ◽  
...  
Keyword(s):  
Team Sports ◽  
High Strength ◽  
Current Strength ◽  
Power Capacity ◽  
Change Of Direction ◽  
Squat Exercise ◽  
Median Split ◽  
Sprinting Speed ◽  
Power Measurements ◽  
Rugby Players

AbstractThe aim of the present study was to investigate the influence of maximum strength and power levels on change of direction (COD) ability and deficit in elite soccer and rugby players. Seventy-eight elite athletes (soccer, n = 46; rugby, n = 32) performed the following assessments: squat and countermovement jumps (SJ and CMJ), 1 repetition-maximum in the half-squat exercise (HS 1RM), peak power (PP) in the jump-squat exercise, and 20-m linear sprint and Zigzag COD tests. Utilizing the median split analysis, athletes were divided into two groups according to their HS 1RM and PP JS (e.g., higher and lower HS 1RM and higher and lower PP JS). The magnitude-based inference method was used to analyze the differences between groups in the physical performance tests. Athletes in the high strength and power groups outperformed their weaker and less powerful counterparts in all speed and power measurements (i.e., 5-, 10-, and 20-m sprint velocity, Zigzag COD speed, and CMJ and SJ height). In contrast, stronger and more powerful athletes displayed greater COD deficits. The present data indicate that players with superior strength-power capacity tend to be less efficient at changing direction, relative to maximum sprinting speed, despite being faster in linear trajectories. From these results, it appears that current strength and power training practices in team-sports are potentially not the “most appropriate” to increase the aptitude of a given athlete to efficiently utilize his/her neuromuscular abilities during COD maneuvers. Nevertheless, it remains unknown whether more multifaceted training programs are effective in decreasing COD deficits.

Moving past the vaccine/autism controversy - to examine potential vaccine neurological harms

2020 ◽  
pp. 1-15
Author(s):  
Peter R. Breggin
Keyword(s):  
Neurological Disorders ◽  
Developmental Disorder ◽  
Physical Symptoms ◽  
Psychosocial Disorders ◽  
The Us ◽  
Potential Vaccine ◽  
Research And Education ◽  
The Brain ◽  
New Vaccines

BACKGROUND: The vaccine/autism controversy has caused vast scientific and public confusion, and it has set back research and education into genuine vaccine-induced neurological disorders. The great strawman of autism has been so emphasized by the vaccine industry that it, and it alone, often appears in authoritative discussions of adverse effects of the MMR and other vaccines. By dismissing the chimerical vaccine/autism controversy, vaccine defenders often dismiss all genuinely neurological aftereffects of the MMR (measles, mumps, and rubella) and other vaccines, including well-documented events, such as relatively rare cases of encephalopathy and encephalitis. OBJECTIVE: This report explains that autism is not a physical or neurological disorder. It is not caused by injury or disease of the brain. It is a developmental disorder that has no physical origins and no physical symptoms. It is extremely unlikely that vaccines are causing autism; but it is extremely likely that they are causing more neurological damage than currently appreciated, some of it resulting in psychosocial disabilities that can be confused with autism and other psychosocial disorders. This confusion between a developmental, psychosocial disorder and a physical neurological disease has played into the hands of interest groups who want to deny that vaccines have any neurological and associated neuropsychiatric effects. METHODS: A review of the scientific literature, textbooks, and related media commentary is integrated with basic clinical knowledge. RESULTS: This report shows how scientific sources have used the vaccine/autism controversy to avoid dealing with genuine neurological risks associated with vaccines and summarizes evidence that vaccines, including the MMR, can cause serious neurological disorders. Manufacturers have been allowed by the US Food and Drug Administration (FDA) to gain vaccine approval without placebo-controlled clinical trials. CONCLUSIONS: The misleading vaccine autism controversy must be set aside in favor of examining actual neurological harms associated with vaccines, including building on existing research that has been ignored. Manufacturers of vaccines must be required to conduct placebo-controlled clinical studies for existing vaccines and for government approval of new vaccines. Many probable or confirmed neurological adverse events occur within a few days or weeks after immunization and could be detected if the trials were sufficiently large. Contrary to current opinion, large, long-term placebo-controlled trials of existing and new vaccines would be relatively easy and safe to conduct.

scholarly journals It’s Time to Change Direction on Agility Research: a Call to Action

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Warren Young ◽  
Russell Rayner ◽  
Scott Talpey
Keyword(s):  
Ecological Validity ◽  
Primary Outcome Measure ◽  
Future Research ◽  
Call To Action ◽  
Change Of Direction ◽  
Movement Component ◽  
Research Questions ◽  
Action Coupling ◽  
Perception Action ◽  
Opinion Article

AbstractAgility is an important skill for both attackers and defenders in invasion sports such as codes of football. On the sporting field, agility requires reacting to a stimulus, often presented by an opponent’s movement, before a change of direction or speed. There is a plethora of research that examines the movement component of agility in isolation, which is described as change-of-direction (COD) ability, and this is thought to underpin agility performance. This opinion article proposes that COD ability should not be researched as the only or primary outcome measure when the objective is to inform agility performance in invasion sports. It is argued that pre-planned COD movements and tests lack ecological validity because they lack perception-action coupling and involve movement out of context from the game. The movement techniques and strength qualities required for the performance of COD tests can be quite different to those required for agility. It is suggested that COD tests can be applied to sports that involve pre-planned COD movements, but researchers should endeavour to use agility tests when studying invasion sports. Some new methods for assessing one-on-one agility contests are reported as potentially valuable for future research, and examples of research questions are provided.

scholarly journals Decrease in regional body fat after long-term high-intensity interval training

2017 ◽  
Vol 6 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Koichiro Azuma ◽  
Yusuke Osawa ◽  
Shogo Tabata ◽  
Fuminori Katsukawa ◽  
Hiroyuki Ishida ◽  
...  
Keyword(s):  
Body Fat ◽  
High Intensity ◽  
Interval Training ◽  
High Intensity Interval Training ◽  
Regional Body Fat ◽  
High Intensity Interval

scholarly journals Comparison of Change of Direction Speed Performance and Asymmetries between Team-Sport Athletes: Application of Change of Direction Deficit

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 174 ◽  
Author(s):  
Thomas Dos’Santos Christopher Thomas ◽  
Paul Comfort ◽  
Paul A. Jones
Keyword(s):  
Completion Time ◽  
Team Sports ◽  
Team Sport ◽  
Linear Speed ◽  
Change Of Direction ◽  
Directional Dominance ◽  
Speed Performance ◽  
Approach Velocity ◽  
Left And Right ◽  
The Relationship

The purpose of this study was twofold: (1) to examine differences in change of direction (COD) performance and asymmetries between team-sports while considering the effects of sex and sport; (2) to evaluate the relationship between linear speed, COD completion time, and COD deficit. A total of 115 (56 males, 59 females) athletes active in cricket, soccer, netball, and basketball performed the 505 for both left and right limbs and a 10-m sprint test. All team-sports displayed directional dominance (i.e., faster turning performance/shorter COD deficits towards a direction) (p ≤ 0.001, g = −0.62 to −0.96, −11.0% to −28.4%) with, male cricketers tending to demonstrate the greatest COD deficit asymmetries between directions compared to other team-sports (28.4 ± 26.5%, g = 0.19–0.85), while female netballers displayed the lowest asymmetries (11.0 ± 10.1%, g = 0.14–0.86). Differences in sprint and COD performance were observed between sexes and sports, with males demonstrating faster 10-m sprint times, and 505 times compared to females of the same sport. Male soccer and male cricketers displayed shorter COD deficits compared to females of the same sport; however, female court athletes demonstrated shorter COD deficits compared to male court athletes. Large significant associations (ρ = 0.631–0.643, p < 0.001) between 505 time and COD deficit were revealed, while trivial, non-significant associations (ρ ≤ −0.094, p ≥ 0.320) between COD deficit and 10-m sprint times were observed. In conclusion, male and female team-sport athletes display significant asymmetries and directional dominance during a high approach velocity 180° turning task. Coaches and practitioners are advised to apply the COD deficit for a more isolated measure of COD ability (i.e., not biased towards athletes with superior acceleration and linear speed) and perform COD speed assessments from both directions to establish directional dominance and create a COD symmetry profile.

scholarly journals Strategy For Cellulase Immobilization And Its Partial Purification And Characterization

2021 ◽  
Author(s):  
Karina Komarova
Keyword(s):  
Active Site ◽  
Partial Purification ◽  
Purification Step ◽  
Purification And Characterization ◽  
Force Microscopy ◽  
Glycosidic Bonds ◽  
Atomic Force ◽  
Lower Glucose ◽  
Force Profile

Conversion of cellulose to glucose units by cellulases, called hydrolysis, is a very complex step in ethanol production. It requires the mixing of aqueous suspensions of cellulose/cellulases so that cellulases (majority composed of the active site domain and the binding site domain) can attach to cellulose chains, cut or hydrolyze ß(1-4) glycosidic bonds between glucose units, de-attach and move to another location. Mixing extent (insufficient or excessive agitation) might influence the attachment of cellulases and possibly lead to lower glucose yields. A long-term goal of this research is to determine the strength of mixing required to be applied during the cellulose-cellulase mixing cycle. For that purpose, one of the objectives was to purify CBH I exocellulase from the commercial cellulase mixture. A partial purification of the CBH I that was performed on a much smaller scale with uncontrolled flow rate was successful. Another objective was to propose a scheme that would covalently immobilize CBH I exoceullase via its active site domain (ASD) on an atomic force microscopy-compatible support, a silicon support. A theoretically-developed hypothetical scheme was constructed (with the provided detailed procedure). The approach of immobilizing the inhibitor specific to the ASD of CBH I enzyme led to the possibility that no purification of CBH I could be required. Skipping CBH I purification step would save time and hassle associated with purification step. Once the ASD of CBH I is immobilized on a silicon support, the AFM force profile between the free-floating CDB and substrate cellulose could be established.

scholarly journals Assessing the Magnitude and Direction of Asymmetry in Unilateral Jump and Change of Direction Speed Tasks in Youth Female Team-Sport Athletes

2021 ◽  
Vol 79 (1) ◽  
pp. 15-27
Author(s):  
Jordi Arboix-Alió ◽  
Chris Bishop ◽  
Ariadna Benet ◽  
Bernat Buscà ◽  
Joan Aguilera-Castells ◽  
...  
Keyword(s):  
Team Sports ◽  
Team Sport ◽  
Kappa Coefficient ◽  
Fitness Testing ◽  
Countermovement Jump ◽  
Linear Speed ◽  
Female Youth ◽  
Change Of Direction ◽  
Time Performance ◽  
The Relationship

Abstract The direction of inter-limb asymmetries and the change of direction (COD) deficit are two aspects that have increased in recent years. The main objective of the present study was to assess the magnitude of neuromuscular asymmetries in an elite youth female team-sports sample and determine its directionality. Secondary objectives were to evaluate the relationship between COD deficit, linear speed and COD time performance. Elite female youth basketball and handball players (n = 33, age = 16 ± 1.17 y) performed the Single Leg Countermovement Jump in vertical (SLCJ-V), horizontal (SLCJ-H), and lateral (SLCJ-L) directions, the COD and the 10-m sprint. Results showed statistical differences between limbs in all the neuromuscular tests (p < 0.001). The Kappa coefficient showed poor to fair levels of agreement between tasks (K range = -0.087 to 0.233), indicating that asymmetries rarely favoured the same limb between skills. Additionally, small and non-significant correlations were found between the linear sprint capacity and the COD ability. The findings of the present study highlight the independent directionality of asymmetries across tests. The COD deficit does not appear to be much more advantageous than COD total time to measure asymmetry. Practitioners are encouraged to use a fitness testing battery to detect existing side differences and each ability should be specifically trained with functional tasks.

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