A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Medicine in the field of Sports Science 15 May 2014 / Introduction: This study sought to determine the relationships between eccentric strength and power of the lower extremity with dynamic balance in male football players. Footballers with superior balance, kick more accurately, have a possible reduced risk of injury and faster agility times. However, the relationship between eccentric strength and power with dynamic balance remains unresolved. Methods: Fifty male footballers (university; n = 27 and professional; n = 23) volunteered to participate in the study and performed the Y-balance Test, eccentric isokinetic knee extensor and flexor testing and the countermovement jump. Results: The university group demonstrated significant positive correlations between mean eccentric peak torque to body weight of the knee extensors and composite score in the Ybalance test (r = 0.42, p = 0.03) and between eccentric peak torque to body weight of the knee extensors of the non-dominant leg with normalised reach distance in the Y-balance test on the non-dominant limb (r = 0.50, p = 0.008). In the professional group, countermovement jump height was significantly correlated with composite score in the Y-balance test (r = 0.52, p = 0.02). Furthermore, countermovement height was positively correlated to normalised reach distance in the Y-balance test on the non-dominant limb in the university (r = 0.4, p = 0.05) and professional (r = 0.56, p = 0.006) groups, respectively. Conclusion: Moderate positive relationships exist between eccentric strength of the knee extensors and dynamic balance in the university group and between power and dynamic balance in the professional group. These findings may be due to different coordination strategies between the groups to maximize reach distance. Both groups demonstrated a significant relationship between countermovement jump height and reach performance on the non-dominant leg. In footballers, different neural control strategies may develop between the limbs due to their constant use of their non-dominant leg to stabilise whilst executing a kicking action. Due to these significant relationships, a longitudinal study measuring the effects of strength and power training on dynamic balance in footballers is required to ascertain cause and effect.

Rapid compensatory reach-to-grasp reactions are prevalent and functionally important responses to instability. The need to react very rapidly (to prevent falling) imposes temporal constraints on acquisition and processing of the visuospatial information (VSI) needed to guide the reaching movement. Previous results suggested that the CNS may deal with these constraints by using VSI stored in memory proactively, prior to perturbation-onset; however, the extent to which online visual control is necessary or sufficient to guide these reactions has not been established. Furthermore, the influence of memory-decay and concurrent cognitive-task on the performance of these reactions has not been examined. This Thesis employed a novel paradigm wherein the participant is stationary and a motor-driven handhold is positioned unpredictably in front of the participant for each trial. Reach-to-grasp reactions were evoked in healthy young and older adults by sudden unpredictable antero-posterior platform translation (barriers deterred stepping reactions). Liquid-crystal goggles were used to occlude vision either before (recall-delay time=0s/2s/5s/10s) or after perturbation-onset to force reliance on either stored- or online-VSI, respectively. Participants performed a spatial- or non-spatial-memory task during the delay-time in a subset of trials. When forced to rely on stored-VSI, all participants showed reduction in reach accuracy; however, a tendency to undershoot the handhold was exacerbated in the older adults. Forced-reliance on online-VSI led to similar delays in all participants; however, the older adults were more likely to reach with the “wrong” arm or raise both arms. Comparison with normal-VSI trials suggests that both sources of VSI are utilized when grasping the movable handhold for support, with stored-VSI predominating during initiation/transport and online-VSI contributing primarily to final target acquisition/prehension. In terms of recall-delay, both age groups showed comparable reduction in medio-lateral endpoint accuracy when delay-time was longest. Moreover, both cognitive tasks had similar (slowing) effects in both age-groups, suggesting these effects were related to generic attentional demands. However, the older-adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory-task. Further research is needed to establish whether interventions aimed to improve visual/cognitive processing speed, visuospatial memory, and/or attention capacity can reduce risk of falling among senior populations.

Rapid compensatory reach-to-grasp reactions are prevalent and functionally important responses to instability. The need to react very rapidly (to prevent falling) imposes temporal constraints on acquisition and processing of the visuospatial information (VSI) needed to guide the reaching movement. Previous results suggested that the CNS may deal with these constraints by using VSI stored in memory proactively, prior to perturbation-onset; however, the extent to which online visual control is necessary or sufficient to guide these reactions has not been established. Furthermore, the influence of memory-decay and concurrent cognitive-task on the performance of these reactions has not been examined. This Thesis employed a novel paradigm wherein the participant is stationary and a motor-driven handhold is positioned unpredictably in front of the participant for each trial. Reach-to-grasp reactions were evoked in healthy young and older adults by sudden unpredictable antero-posterior platform translation (barriers deterred stepping reactions). Liquid-crystal goggles were used to occlude vision either before (recall-delay time=0s/2s/5s/10s) or after perturbation-onset to force reliance on either stored- or online-VSI, respectively. Participants performed a spatial- or non-spatial-memory task during the delay-time in a subset of trials. When forced to rely on stored-VSI, all participants showed reduction in reach accuracy; however, a tendency to undershoot the handhold was exacerbated in the older adults. Forced-reliance on online-VSI led to similar delays in all participants; however, the older adults were more likely to reach with the “wrong” arm or raise both arms. Comparison with normal-VSI trials suggests that both sources of VSI are utilized when grasping the movable handhold for support, with stored-VSI predominating during initiation/transport and online-VSI contributing primarily to final target acquisition/prehension. In terms of recall-delay, both age groups showed comparable reduction in medio-lateral endpoint accuracy when delay-time was longest. Moreover, both cognitive tasks had similar (slowing) effects in both age-groups, suggesting these effects were related to generic attentional demands. However, the older-adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory-task. Further research is needed to establish whether interventions aimed to improve visual/cognitive processing speed, visuospatial memory, and/or attention capacity can reduce risk of falling among senior populations.

Issued also as thesis, Utrecht.

Issued also as thesis, Utrecht.

Thesis (M.Sc.). / Written for the School of Physical and Occupational Therapy. Title from title page of PDF (viewed 2009/06/25). Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:29:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-15Bitstream added on 2014-06-13T19:59:56Z : No. of bitstreams: 1 barral_abcr_me_botfm.pdf: 1083906 bytes, checksum: 2d72bd5b6c72ef6ae4548136776159d9 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Verificar os efeitos da terapia hormonal (TH) sobre o equilíbrio postural em mulheres na pós-menopausa e sua associação com o risco de quedas. Realizou-se estudo transversal com 225 mulheres, idade 45-75 anos, atendidas em Hospital Universitário. As participantes foram divididas em dois grupos: usuárias de TH (n=102) e não usuárias (controle, n=123). Incluíram-se mulheres com amenorréia >12 meses e idade ≥ 45 anos. E se excluíram aquelas com doenças neurológicas ou musculoesqueléticas, história atual de vestibulopatias, déficit visual sem correção, obesidade grau III, usuárias de drogas que alterem o equilíbrio. Consideraram-se usuárias de TH aquelas que faziam uso contínuo há pelo menos seis meses. Foram analisados o histórico de quedas (últimos 24 meses) e as características clínicas e antropométricas. O equilíbrio postural foi avaliado pela estabilometria (plataforma de força), pelo teste de Romberg, pelo alcance funcional e teste do agachamento. Para análise estatística foram empregados o Teste da Mediana, o teste do Qui-Quadrado, regressão logística no risco para queda (odds ratio-OR) e o coeficiente de correlação de Spearman. As mulheres usuárias de TH eram mais jovens (53,0 anos vs 57 anos) e de menor tempo de menopausa (5,5 anos vs 10,0 anos) quando comparadas as não usuárias (p<0,05), sem diferenças antropométricas. A frequência de quedas foi significativamente menor entre as usuárias de TH quando comparadas as não usuárias, 51 vs 88 quedas, respectivamente (p<0,05), que apresentaram risco ajustado de 0,49 (IC 95% 0,27-0,88) vez menor para quedas que o grupo de não usuárias. Nos parâmetros estabilométricos, as usuárias de TH apresentaram significantemente menor amplitude de deslocamento latero-lateral e ântero-posterior e menor área de deslocamento quando comparadas as não usuárias (p<0,05). No teste de Romberg notou-se aumento... / To analyze the effects of hormone therapy (HT) on postural balance in postmenopausal women and its association with risk for falls. A crosssectional study was conducted on 225 women aged 45-75 years and cared for at the outpatient clinic of a University Hospital. The participants were divided into two groups: HT users (n=102) and non-users (control, n=123). Women in amenorrhea >12 months and age ≥ 45 years were included. Those with neurological or musculoskeletal disorders, current history of vestibulopathies, uncorrected visual deficit, level-III obesity or drug use that could affect balance were excluded. Women utilizing continuous HT for at least 6 months were considered to be HT users. Histories of falls (last 24 months) as well as clinical and anthropometric characteristics were analyzed. Postural balance was assessed by stabilometry (computerized force platform), Romberg’s test, functional reach test and the crouching test. For statistical analysis were used: the Median test, the Chi-square test, the logistic regression method (odds ratio- OR) for fall risk, and Spearman’s correlation coefficient. Women users of HT were younger (53.0 years vs. 57 years) and had been menopausal for a shorter period of time (5.5 years vs. 10.0 years) as compared to non-users (p<0.05); no anthropometric differences were observed. The frequency of falls was significantly lower among HT users as compared to non-users, 51 vs. 88 falls, respectively (p<0.05), that presented an adjusted risk of 0.49 (CI 95% 0.27-0.88) time lower of falls than the non-users group. With respect to the stabilometric parameters, HT users showed significantly lower amplitude in latero-lateral and antero-posterior oscillation and a smaller oscillation area as compared to non-users (p<0.05). Romberg’s test showed progressive positive increase as the test difficulty increased; however, significant differences were... (Complete abstract click electronic access below)

Background: Concussion assessments rely on a multifaceted approach where evaluation of balance and postural control plays an important role. Following a concussion, 67% of individuals report dizziness as a persistent symptom and 30% experience balance impairments. Studies incorporating the common Balance Error Scoring System (BESS) tool suggest that these impairments return to pre-injury baselines within ten days of incident. In contrast, however, studies incorporating more advanced posturography methods observe significant differences in balance up to one year following injury. While the BESS is consistently associated with low sensitivity and poor reliability scores, advanced posturography systems using force plates are not practical or accessible in most recreational sports environments. Recently, the Wii Balance Board (WBB) has been identified as a potential force plate proxy. Research confirms that the WBB is both valid and reliable in collecting center of pressure data. Thus, the WBB may be useful for investigating post-concussion balance deficits. Objective: The purpose of this study was to investigate the potential utility of a customized WBB program to assess postural balance in an athletic population. The study aimed to assess change in postural balance using the clinical BESS and WBB assessment tools to evaluate balance at fixed intervals during a regular athletic season and following concussion. Design: Prospective partial cohort. Methods: Balance was assessed at baseline, mid-, and post-season. Individuals who sustained a concussion during the study period were further assessed weekly for four weeks post-injury. Results: No significant differences were observed in raw BESS scores across regular season or post-concussion time points. In contrast, significant differences in several WBB outcome measures were observed. In the single stance condition, COPML worsened by 24% and COPT worsened by 9% between baseline and post-season time points (p=.002 and p=.007). In contrast, participants improved by 14% on a timed dynamic task (p=.003) between baseline and post-season time points. Following concussion, only the WBB dynamic outcome measures were found to be statistically significant. A positive trend was observed post-concussion, suggesting that a learning effect exists with the dynamic WBB program. Conclusion: Study results emphasize the importance of considering the progression of athletic season when interpreting baseline and post-concussion balance measurements. Study results support the use of a quantitative balance assessment, such as with a WBB, to improve measurement of static and dynamic postural balance. / Graduate / 0566 / hilarymcullen@gmail.com

INTRODUÇÃO: Atletas de futebol podem ter melhor equilíbrio que sedentários, pois os programas de treinamento sensório-motor melhoram a função motora, aumentam o controle neuromuscular e promovem a melhora da propriocepção. Este estudo teve como objetivos: avaliar o equilíbrio postural e a influência da dominância e dos fatores antropométricos em atletas de futebol de campo e indivíduos sedentários. MÉTODOS: Foram avaliados 100 indivíduos do gênero masculino divididos em dois grupos: 50 atletas de futebol de campo (GA) com idade de 18,0+0,7 anos e 50 indivíduos sedentários (GS) com idade de 17,6+0,6 anos. Os grupos foram analisados em relação à massa corporal, estatura, índice de massa corporal (IMC), flexibilidade e percentagem de gordura. Para avaliação do equilíbrio foi utilizado o protocolo Dynamic Balance System, nível 8 de estabilidade do equipamento Biodex Balance System (BBS). RESULTADOS: Os atletas apresentaram melhores índices no membro dominante no teste para a direita (p = 0,039) e no membro não-dominante no teste para trás/esquerda (p=0,007). Os sedentários tiveram melhores índices no teste realizado para a direita (p=0,034) no membro não dominante. Nos demais índices, não houve diferença estatística. O GS teve melhor desempenho do membro não dominante quando comparado com o dominante na maioria dos testes realizados. No GA houve melhor desempenho do membro não dominante no índice de estabilidade geral (p=0,027) e para esquerda (p=0,009). Houve fraca correlação entre medidas antropométricas e os índices de equilíbrio medidos pelo BBS nos dois grupos. CONCLUSÕES: Não há diferença no equilíbrio postural de atletas de futebol de campo e indivíduos sedentários. A dominância afeta o equilíbrio unipodal dos indivíduos sedentários, mas não afeta dos atletas de futebol de campo da categoria juniores. Os fatores antropométricos não interferiram no equilíbrio / INTRODUCTION: Soccer athletes may have a better balance than sedentary individuals, once sensory-motor training programs improve the motor function, increase neuromuscular control and promote a better balance and proprioception. The aim of this study was to assess the postural balance and the influence of the dominance and of anthropometric measures on field soccer athletes and sedentary individuals. METHODS: One hundred male individuals were assessed and divided in two groups: 50 field soccer players (AG) aged 18+0,7 years and 50 sedentary individuals (SG) aged 17,6+0,6 years. Groups were analyzed regarding body mass, height, body mass index (BMI), flexibility and fat percentage. Balance was assessed using the Dynamic Balance System protocol, level 8 of stability of the Biodex Balance System (BBS) equipment. RESULTS: Athletes presented better indexes in the dominant member in the test performed to the right (p=0,039), and in the non-dominant member in the test to backward/left (p=0,007). Sedentary individuals presented better indexes in the test performed to the right (p=0,034) in the non-dominant member. There was no statistical difference in the other tests. The SG presented better performance of the non-dominant member when compared to the dominant member in most of the tests performed. In the AG, there was a better performance of the non-dominant member in the overall stability index (p=0,027) and to the left (p=0,009). There was poor correlation between anthropometric measures and balance indexes measured by the BBS in both groups. CONCLUSIONS: There was no difference in postural balance between field soccer athletes and sedentary individuals. The dominance affected the unipodal balance of sedentary individuals, but not of field soccer athletes from the junior category. The anthropometric indexes did not interfere in the postural balance

O presente estudo objetivou analisar a relação do índice do arco plantar com o equilíbrio postural e com a frequência do uso do salto alto entre mulheres de diferentes faixas etárias. Participaram do estudo 60 mulheres, 20 no grupo jovem (GJ), 20 no grupo adulto (GA) e 20 do grupo idoso (GI), as quais foram separadas em subgrupos com 10 indivíduos cada de acordo com a frequência do uso do salto alto. A avaliação da frequência do uso do sapato de salto alto foi realizada através do número de vezes que o indivíduo utilizava esse tipo de calçado. Para o cálculo do índice do arco plantar (IAP) utilizou-se o método de impressão plantar, por meio de um pedígrafo. Para a aquisição dos dados referentes ao equilíbrio postural foi utilizada uma plataforma de força AMTI; as variáveis utilizadas a partir do Centro de Pressão (COP) foram: amplitude de deslocamento ântero-posterior do centro de pressão (COPap), amplitude de deslocamento médio-lateral do COP (COPml), velocidade média de deslocamento do COP (COPvel) e área da elipse (elipse). Os resultados apontam que não houve correlações entre as variáveis do COP (COPap, COPml, velocidade e elipse) e o IAP na condição de olhos abertos e olhos fechados. Ao se tratar da faixa etária, houve diferença estatisticamente significativa entre o índice do arco plantar do GJ e GI e do GA e GI, indicando que o grupo de mulheres idosas possui um maior índice do arco plantar, ou seja, um rebaixamento no arco longitudinal medial. Com relação à frequência do uso do salto alto, não houve diferença estatisticamente significativa do índice do arco plantar entre os grupos. Concluiu-se que o índice do arco plantar não altera o controle postural em mulheres jovens, adultas e idosas deste estudo e que o grupo idoso apresenta um rebaixamento do arco longitudinal medial quando comparado com o grupo jovem e adulto. / The present study aimed to analyze the relationship between plantar arch index and postural balance and the frequency of use of high-heeled shoes among women of different age groups. The study included 60 women, 20 in the young group (GJ), 20 in the adult group (GA) and 20 in the elderly group (GI), which were separated into groups with 10 individuals each according to frequency of use of high-heeled shoes. The evaluation of the frequency of use of the high heel shoe was performed using the number of times that the person use this kind of footwear. To obtain the plantar arch index (IAP) was used the method of printing plant, with a plantar foot pressure. For acquisition of postural balance data was used a AMTI force plate and variables from the center of pressure (COP) used were: range of anteroposterior displacement of the center of pressure (COPap), range of displacement of the medial-lateral COP (COPml) and average speed of displacement of the COP (COPvel). The results showed that there were no correlations between the variables of COP (COPap, COPml, speed and ellipse) and IAP on eyes opened and eyes closed conditions. When dealing with the age group, there were statistically significant differences between the plantar arch index of the GJ and GI and of the GA and GI, indicating that the group of older women have an increased plantar arch index or a presents lower medial longitudinal arch. It was concluded that the plantar arch index does not alter postural control in young, adult and elderly people and that the elderly group presents lower medial longitudinal arch when compared with the young adult group showing.