The back is subjected to a great deal of strain in many sports. Up to 20% of all sports injuries involve an injury to the lower back or neck. Repetitive or high impact loads (e.g., running, gymnastics, skiing) and weight loading (e.g., weightlifting) affect the lower back. Rotation of the torso (e.g., golf, tennis) causes damage to both, the lumbar and thoracic spine. The cervical spine is most commonly injured in contact sports (e.g., boxing, football). One of the factors that increases the odds of injuries in athletes is excessive and rapid increases in training loads. In spite of currently emerging evidence on this issue, little is known about the balance between physiological loading on the spine and athletic performance, versus overloading and back pain and/or injury in athletes. This scoping review aims (i) to map the literature that addresses the association between the training load and the occurrence of back pain and/or injury, especially between the Acute:Chronic Workload Ratio (ACWR) and back problems in athletes of individual and team sports, and (ii) to identify gaps in existing literature and propose future research on this topic. A literature search of six electronic databases (i.e., MEDLINE, PubMed, Web of Science, SCOPUS, SportDiscus, and CINAHL) was conducted. A total of 48 research articles met the inclusion criteria. Findings identified that fatigue of the trunk muscles induced by excessive loading of the spine is one of the sources of back problems in athletes. In particular, high training volume and repetitive motions are responsible for the high prevalence rates. The most influential are biomechanical and physiological variations underlying the spine, though stress-related psychological factors should also be considered. However, limited evidence exists on the relationship between the ACWR and back pain or non-contact back injuries in athletes from individual and team sports. This may be due to insufficiently specified the acute and chronic time window that varies according to sport-specific schedule of competition and training. More research is therefore warranted to elucidate whether ACWR, among other factors, is able to identify workloads that could increase the risk of back problems in athletes.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The authors investigate the ways in which varied postural responses to translating platform perturbations are associated with the variables of strength and power. Twenty-four physically active and 27 sedentary young adults were exposed to a set of postural perturbations at varied velocities (10 and 20 cm/s) and the respective accelerations (6.4 and 6.9 m/s2), constant distance (6 cm), and 4 directions of platform motion (forward, backward, left-lateral, and right-lateral). They also performed maximum voluntary isometric contraction (MVC) and chair rising/chair jumping tests. The analysis of variance revealed significant interaction effect for peak center of pressure displacement, direction by velocity: F3,129= 24.43, p = .002; and direction by acceleration: F3,129= 34.18, p = .001. There were no significant correlations between peak center of pressure displacements and peak force and peak rate of force development measured during MVC in either standing (r = .27-57) or sitting positions (r = .12-51) and peak power during chair jumping (r = .47-.59) in all participants. As such, only a small proportion of variance was explained (9-39%, 3-23%, and 23-41%, respectively). In conclusion, interaction effects indicate that the composition of stimuli strongly influences compensatory responses and this effect is more pronounced in sedentary than in physically active young adults. Nevertheless, the dynamic balance is not associated with muscle strength and power in either group.
- MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- postura těla fyziologie MeSH
- posturální rovnováha fyziologie MeSH
- sedavý životní styl MeSH
- svalová síla fyziologie MeSH
- tělesná výkonnost MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
This study compares postural and trunk responses to translating platform perturbations of varied velocities and directions. A group of 18 young and physically active subjects were exposed to a set of postural perturbations at varied velocities (5, 10, 15, and 20 cm/s) and directions of platform movement (forward, backward, left-lateral, and right-lateral). The center of pressure (CoP) displacement measurement, in addition to the trunk motion (representing the center of mass (CoM) displacement), were both monitored. Results identified that the CoP displacement increased from slow to faster velocities of platform motion more widely in both anterior and posterior directions (50.4 % and 48.4 %) as compared to the CoM displacement (17.8 % and 14.9 %). However a greater increase in the peak CoM velocity (70.3 % and 69.6 %) and the peak CoM acceleration (60.5 % and 53.1 %) was observed. The values in the anterior and posterior direction only differed significantly at the highest velocity of platform motion (i.e. 20 cm/s). A similar tendency was observed in the medio-lateral direction, but there were no significant differences in any parameter in the left-lateral and right-lateral direction. The velocity of the platform motion highly correlated with peak velocity (r=0.92-0.97, P<0.01) and moderately with amplitude of trunk displacement (r=0.56-0.63, P<0.05). These findings indicate that the velocity of perturbation alters peak CoM velocity rather than the magnitude of CoM displacement. The effect of the direction of perturbations on the trunk response emerges only at a high velocity of platform motion, such that the peak CoM velocity and peak CoM acceleration are significantly greater in anterior than posterior direction.
- MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- posturální rovnováha fyziologie MeSH
- trup fyziologie MeSH
- zdraví dobrovolníci pro lékařské studie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
The study compares the differences in peak and mean power of concentric-only and countermovement resistance exercises (ΔP) with different weights. A group of 27 fit men randomly performed 3 repetitions of either barbell bench presses or barbell squats on different days. The initial weight of 20 kg was increased by 10 or 5 kg (at higher loads) up to at least 85% of a previously established 1 repetition maximum (1RM). A computer-based system FiTRO Dyne Premium was used to monitor force and velocity and to calculate power. The peak values and mean values of power during the entire concentric phase of lifting and during the acceleration phase were analyzed. Results showed that maximal ΔP calculated from the peak and mean values in the acceleration phase of bench presses was achieved at lower weights (118.4 ± 19.0 W at 47% of 1RM and 116.2 ± 15.3 W at 48% of 1RM, respectively) than the one calculated from mean values in the entire concentric phase of lifting (114.8 ± 14.8 W at 57% 1RM). Likewise, maximal ΔP calculated from the peak and mean values in the acceleration phase of squats was achieved at lower weights (127.7 ± 20.4 W at 67% of 1RM and 124.3 ± 22.1 W at 69% of 1RM, respectively) than the one calculated from the mean values in the entire concentric phase of lifting (125.0 ± 19.2 W at 77% of 1RM). This fact has to be taken into account when training efficiency is evaluated, namely, in sports requiring the production of maximal force in a short time.
- MeSH
- biomechanika MeSH
- dospělí MeSH
- ergometrie MeSH
- kosterní svaly fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- náhodné rozdělení MeSH
- odporový trénink * MeSH
- svalová síla * MeSH
- vzpírání fyziologie MeSH
- zátěžový test MeSH
- zrychlení MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The study evaluates a reaction time in the Agility Test under simulated competitive and noncompetitive conditions. A group of 16 fit men performed, in random order, 2 versions of the Agility Test: non-competitive Agility Single and Agility Dual in form of simulated competition. In both cases, subjects had to touch, as fast as possible, with either the left or the right foot 1 of 4 mats located in 4 corners outside of an 80 cm square. Mats had to be touched in accordance with the location of the stimulus in one of the corners of the screen. The test consisted of 20 visual stimuli with random generation of their location on the screen and time generation from 500 to 2,500 milliseconds. The result was total reaction time (RT) for all 20 reactions measured by a PC-based system FiTRO Agility Check. Results showed significantly (p < 0.01) better RT in the Agility Dual than in the Agility Single Test (690.6 ± 83.8 milliseconds and 805.8 ± 101.1 milliseconds, respectively). Further comparisons of RT under noncompetitive and simulated competitive conditions for the best 8 subjects proceeded in the second match showed a decrease from 781.3 ± 111.2 milliseconds to 693.6 ± 97.8 milliseconds in the first match and to 637.0 ± 53.0 milliseconds in the second match. It may be concluded that RT is better when the Agility Test is performed in simulated competitive than noncompetitive conditions. The Agility Test in form of competition may be used for children and young athletes to enhance their attention level and motivation.
1. vyd. 96 s. : il., tab. ; 21 cm
- Konspekt
- Fyziologie člověka a srovnávací fyziologie
- NLK Obory
- fyziologie
- NLK Publikační typ
- učebnice vysokých škol
- MeSH
- diagnostické techniky a postupy statistika a číselné údaje využití MeSH
- diagnostické vybavení využití MeSH
- financování organizované MeSH
- lidé MeSH
- postura těla MeSH
- posturální rovnováha fyziologie MeSH
- senioři MeSH
- sporty MeSH
- svalová síla - dynamometr využití MeSH
- tělesná námaha MeSH
- tělesná výchova MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- Publikační typ
- grafy a diagramy MeSH
Práca sa zaoberá diagnostikou výbušnej sily dolných končatín u rockenrollistov. Vyšetrených bolo 18 reprezentantov v rockenrolle (9 chlapcov a 9 dievčat). Na posudzovanie odrazovej výbušnosti dolných končatín a schopnosti udržať si jej úroveň po dlhší čas bol použitý test 10- a 60, resp. 90-sekundových opakovaných znožných výskokov na výskokovom ergometri. Výsledky ukázali, že v porovnaní s bežnou populáciou mali rockenrollisti výbornú úroveň odrazových schopností dolných končatín. Dievčatá síce disponovali nevýznamne vyššou úrovňou odrazovej výbušnosti ako chlapci, ale nižšou schopnosťou udržať ju počas dlhšie trvajúceho zaťaženia. V priebehu štvorročného tréningového cyklu sa výbušná sila dolných končatín výrazne nezmenila ani u chlapcov ale ani u dievčat. Na druhej strane schopnosť udržať jej úroveň po dlhší čas sa u dievčat zmenila v zmysle zvýšenia indexu únavy v závere 60-sekundového testu, avšak u chlapcov bola táto úroveň aj po štyroch rokoch približne rovnaká. Takáto laboratórna diagnotika trénovanosti v rockenrolle predstavuje dôležitý ukazovateľ tak z aspektu výberu talentov, ako aj hodnotenia aktuálneho stavu limitujúcich faktorov štruktúry športového výkonu.
The papers deals with diagnostics of explosive power of lower limbs in rock and roll dancers. A group of 18 top representatives in rock and roll (9 boys and 9 girls) were examined. For the evaluation of explosive power of lower limbs and their endurance a 10 and 60 / 90 second tests on jump ergometer were used. Results showed that power in the active phase of take-off in 10 second test on jump ergometer was slightly higher in girls than in boys. In comparison with general population these athletes reached the zone "excellent“. In 90 second load on jump ergometer girls reached during the first ten seconds higher power in the active phase of take-off than boys, but in the end of the test higher values were found in boys than in girls. The fatigue index was not significantly higher in girls than in boys. During four years of the training period there were no significant differences in the power output measured in ten second test between girls and boys. The fatigue index in sixty second test increased in girls but not in boys. The laboratory tests used in the investigation demonstrated that they are suitable methods for talent identification and evaluation of limiting factors of sport performance in rock and roll dancers.
