Symmetry in the front crawl stroke of different skill level of able-bodied and disabled swimmers

Copyright: © 2020 Santos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Although swimming is recognized as a symmetrical sport, equivalence between each body side cannot be insured. Swimmers with physical and motor impairment may present asymmetries that are even more pronounced. Therefore, the objective of this study was to assess the symmetry of temporal coordination in the front crawl stroke phases and their dimensional characteristics among swimmers of different levels of skill and disabled swimmers. Forty-one swimmers (28 men and 13 women, 18,8 ± 3,3 years, divided 21 of them into groups of high and low level of skill and 20 in disabled swimmers group) performed a 50m maximum of front-crawl test while they were recorded by six synchronized cameras (four underwater and two above water) for analysis of the stroke phases, stroke dimensions (anteroposterior, mediolateral and vertical amplitude), index of coordination and hand speed. The symmetry index was calculated by the difference between the right and the left strokes. Comparisons were made using the Kruskal-Wallis test and multivariate comparisons were made using the Mann-Whitney test, with p <0.05. Asymmetry was noted in anteroposterior and mediolateral amplitudes of the stroke, index of coordination, duration of the recovery phase, each of the underwater phases and in the hand speed during the downseep phase, regardless of the level of skill or impairment. The disabled swimmers also showed asymmetry in the vertical amplitude of the stroke as well as in the insweep and upsweep speed. The reasons for these asymmetries may be the preference for unilateral breathing, force imbalance between pairs of homologous muscles and motor control deficit. The training with stereotypic movements may explain the similarity of asymmetries among the different groups of swimmers

A cross‐sectional analysis of the muscle strength, spinal shrinkage, and recovery during a working day of military police officers

Objective: Military personnel has a large prevalence of back pain, especially those involved in patrolling routines, as they wear heavy protective equipment. Patrolling includes long periods of sustaining the protective equipment in a sitting or in a motor vehicle (motorcycle or car). Thus, understanding spinal loading of military police officers after patrolling by car (CAR; n = 14), motorcycle (MOT; n = 14), and administrative (ADM; n = 14) routines is relevant to establish preventive strategies. Methods: The torque of the trunk and working and anthropometric characteristics were assessed to explain spinal loading using stature variation measures. Precise stature measures were performed before and after a 6 h journey (LOSS) and 20 min after a resting posture (RECOV). The trunk extensor (PTE BM−1) and flexor (PTF BM−1) muscles' isometric peak torque were measured before the working journey. Results: The LOSS was similar between CAR and MOT (4.8 and 5.8 mm, respectively) after 6 h of patrolling. The ADM presented the lowest LOSS (2.8 mm; P .05). Vibration may explain the greater spinal loading involved in patrolling in comparison to the ADM. A GLM analysis revealed that BMI was the only explanatory factor for stature loss. No independent variables explained RECOV. The ability of the trunk muscles to produce force did not influence LOSS or RECOV. Conclusions: Military police officers involved in patrolling may require greater post‐work periods and strategies designed to reduce the weight of the protective apparatus to dissipate spinal loading. The external load used in patrolling is a relevant spinal loading factor

Front crawl swimming performance and bi-lateral force asymmetry during land-based and tethered swimming tests

©Journal of Sports Science and Medicine. The aims of this study were to investigate whether land-based and tethered swimming strength tests can explain swimming performance in 200-meter front crawl and, whether these tests were able to identify bilateral symmetry in force production. In the first session, eighteen swimmers completed a maximum effort 200 m front crawl swim (swimming performance) and 15 seconds maximal effort tethered front crawl swim. In the second session, participants performed the upper extremity isometric strength test. Peak force production of tethered swimming and isometric strength tests were significantly correlated for the strongest and weakest sides (r = 0.58 and r = 0.63, respectively; p < 0.05), but only peak force production during tethered swimming correlated with 200 m swimming performance time (r = -0.55, p < 0.05). Bilateral asymmetries in peak force and rate of force development were similar between the tethered swimming and isometric strength tests (peak force: 13%, p = 0.24; rate of force development: 15%, p = 0.88) However, both tests detected significant difference of peak force and rate of force development between body sides. The tethered swimming test can partially explain the 200 m front crawl swimming performance. In addition, the land-based and tethered swimming tests may be used to identify bilateral asymmetry of swimming

Changes in stature during and after spinal traction in young male subjects Alterações na estatura antes e após a tração vertebral em homens jovens

BACKGROUND: Spinal traction is a relatively popular procedure for increasing the intervertebral space by applying separating forces. The parameters of time and magnitude of the traction forces may influence the outcomes from this procedure and need to be investigated. The duration of the benefits derived from traction is unknown and needs to be determined so that physiotherapists can provide better and more effective treatments. OBJECTIVE: This study analyzed the relationship between load magnitude and time during spinal traction in relation to stature variations. Traction effect duration was also analyzed. METHOD: Fifteen healthy male subjects (23.1 &plusmn; 5.77 years; 1.80 &plusmn; 0.17 m and 87.0 &plusmn; 9.6 kg) were assessed under three traction conditions (0, 30 and 60% of body weight, BW) of 42 minutes. Stature variation was used to determine intervertebral disc height variation. Stature was assessed every 7 minutes during traction of 42 minutes and every 5 minutes for 45 minutes after traction ceased. RESULTS: 0 and 30% BW traction produced similar gains (6.09 &plusmn; 1.89 mm, 5.70 &plusmn; 1.88 mm, respectively; p>0.05), while these were smaller (p<0.05) than at 60% BW (7.01 &plusmn; 1.98 mm). Significant differences (p<0.05) between 60% BW and the other conditions occurred only after the 21st minute. Stature loss after traction showed that the traction effects were transient and lasted for approximately one hour. This suggests that traction loads of 30% BW are insufficient to produce stature gains similar to those observed with 60% BW. CONCLUSION: Traction showed a short-duration transient effect. For this effect to be maintained, it must be repeated at one-hour intervals. Its use is questioned because of its transient nature.<br>CONTEXTUALIZAÇÃO: A tração sobre a coluna vertebral é um procedimento relativamente popular para aumentar o espaço inter-vertebral pela aplicação de forças de separação. Os parâmetros de tempo e magnitude da força aplicada podem influenciar os resultados desse procedimento e ainda precisam ser investigados. A duração dos benefícios derivados da tração não é conhecida e precisa ser determinada para que fisioterapeutas possam prover tratamentos melhores e mais eficientes. OBJETIVO: Este estudo analisou a relação entre a magnitude de carga e de tempo durante a tração vertebral sobre as variações de estatura, bem como a duração deste efeito. MÉTODOS: Quinze sujeitos saudáveis do sexo masculino (23,1 &plusmn; 5,77 anos; 1,80 &plusmn; 0,17 m e 87,0 &plusmn; 9,6 Kg) foram mensurados sob três condições (0, 30 e 60% PC) de 42 minutos. A variação de estatura foi utilizada para determinar a variação da altura dos discos intervertebrais. A estatura foi verificada a cada 7 min durante a tração de 42 min e a cada 5 min por 45 min após o término da tração. RESULTADOS: A tração com 0 e 30% do PC produziu ganhos similares (6,09 &plusmn; 1,89mm, 5,70 &plusmn; 1,88mm, respectivamente; p>0,05), que foram menores (p<0,05) que com 60% do PC (7,01 &plusmn; 1,98 mm). Diferenças significativas (p<0,05) entre 60% do PC e outras condições ocorreram apenas após o 21&deg; min. A perda de estatura após a tração demonstrou que os efeitos da tração vertebral são transientes e duram aproximadamente 1 hora. Isso sugere que a carga de tração de 30% PC não é suficiente para produzir ganhos de estatura similares aos observados com 60% PC. CONCLUSÃO: A tração demonstrou um efeito transiente e de curta duração, para esse efeito ser mantido ele deve ser repetido em intervalos de 1 hora. O uso da tração é questionado devido ao seu efeito transiente

The effects of upper limb loading on spinal shrinkage during treadmill walking

Everyday activities such as walking either loaded or unloaded may elicit spinal shrinkage in an order of magnitude that has been related to lower back pain. The present study aims to compare the effects of unloaded treadmill walking with walking carrying loads representing everyday shopping tasks. Walking tasks were performed on 7 healthy males, consisting of unloaded walking and walking carrying 7.5% and 15% of body weight. Motion analysis was used to track four reflective markers at 100Hz, dividing the spine into three segments and static data was collected in 5 minute intervals over a 30 minute period. Total spine and segment length changes were compared to original length in the sagittal plane and the effects of load, time and their interaction were analysed using ANOVA. Total spinal length and lumbar segment decreased with respect to time (p < 0.001). Load affected the percentage length change at each spinal segment (p < 0.005), with the lumbar segment showing greatest height loss at the highest load. Inter-segmental variations in length resulted in the non-significant effect of load on the percentage length change of the total spine (P = 0.263). The upper and lower thoracic segments showed greater anterior lean with the heavier loads (p = 0.000) and the lumbar segment showed the opposite trend (p = 0.000). Results suggest that the body adopts less anterior lean with an immediate load bearing demand, to decrease the flexion moment arm of the load about the lumbar spine and thus decrease the necessary extension moment generated by the spinal extensors for spinal stability. Further postural alteration in the same direction is observed with prolonged loading. In combination with lumbar spinal shrinkage, such postural changes are likely to increase the loading on the facet joints with potential deleterious consequences for low back pai

Análise radiográfica da coluna cervical em indivíduos assintomáticos submetidos a tração manual Radiographic analysis of the cervical spine in healthy individuals submitted to manual traction

OBJETIVO: Avaliar, radiograficamente, o efeito da tração manual sobre o comprimento da coluna cervical. MATERIAIS E MÉTODOS: Cinqüenta e cinco participantes de ambos os gêneros - 12 masculinos (22%) e 43 femininos (78%) - sem história de distúrbios cervicais contituíram a amostra deste estudo. Eles foram submetidos a dois procedimentos radiológicos, um antes e outro durante a tração manual sustentada por 120 segundos. As distâncias entre as bordas anteriores e posteriores da segunda à sétima vértebras cervicais foram mensuradas e comparadas antes e durante a tração manual. RESULTADOS: A mediana da distância anterior antes da tração foi de 8,40 cm e durante a tração aumentou para 8,50 cm (p=0,002). A mediana da distância posterior antes da tração foi de 8,35 cm e durante a tração aumentou para 8,50 cm (p<0,001). CONCLUSÃO: Os resultados demonstraram que a aplicação da tração manual promoveu aumento estatisticamente significante do comprimento da coluna cervical em indivíduos assintomáticos.<br>OBJECTIVE: To evaluate radiographically the effect of manual traction on the length of the cervical spine in healthy individuals. MATERIALS AND METHODS: The sample of the present study included 55 individuals - 12 men (22%) and 43 women (78%) - with no previous history of cervical disorders, submitted to two radiological procedures previously and during manual traction sustained for 120 seconds. Distances between the anterior and posterior edges from the second to the seventh cervical vertebrae were measured and compared before and during manual traction. RESULTS: The median of pre-traction anterior length was 8.40 cm, increasing to 8.50 cm during the traction (p=0.002); and the median of pre-traction posterior length was 8.35 cm, increasing to 8.50 cm during traction (p<0.001). CONCLUSION: Application of manual traction resulted in a statistically significant increase in the length the cervical spine in healthy individuals