Juliana Usman

An investigation of shoulder forces in active shoulder tackles in rugby union football

In rugby union football the tackle is the most frequently executed skill and one most associated with injury, including shoulder injury to the tackler. Despite the importance of the tackle, little is known about the magnitude of shoulder forces in the tackle and influencing factors. The objectives of the study were to measure the shoulder force in the tackle, as well as the effects of shoulder padding, skill level, side of body, player size, and experimental setting on shoulder force. Experiments were conducted in laboratory and field settings using a repeated measures design. Thirty-five participants were recruited to the laboratory and 98 to the field setting. All were male aged over 18 years with rugby experience. The maximum force applied to the shoulder in an active shoulder tackle was measured with a custom built forceplate incorporated into a 45 kg tackle bag. The overall average maximum shoulder force was 1660 N in the laboratory and 1997 N in the field. This difference was significant. The shoulder force for tackling without shoulder pads was 1684 N compared to 1635 N with shoulder pads. There was no difference between the shoulder forces on the dominant and non-dominant sides. Shoulder force reduced with tackle repetition. No relationship was observed between player skill level and size. A substantial force can be applied to the shoulder and to an opponent in the tackle. This force is within the shoulders injury tolerance range and is unaffected by shoulder pads.

Upper limb injury in rugby union football: results of a cohort study

Background There have been few in-depth studies of upper limb injury epidemiology in rugby union football, despite reports that they accounted for between 14% and 28% of all rugby injuries. Objective To report on upper limb injury incidence, injury severity and to identify the risk factors associated with upper limb injuries, for example, level of play, season (years) and playing position. Design Prospective cohort study across five rugby seasons from 2004 to 2008. Setting Formal rugby competitions—suburban, provincial and international. Participants 1475 adult male rugby players in Colts, Grade and Elite competitions. Main outcome measurements An upper limb injury resulting in a missed game and its characteristics. Results A total of 61 598 athletic exposures (AE) and 606 upper limb injuries were recorded. About 66% of the injuries were to the shoulder. The overall upper limb injury incidence rate (IIR) was 9.84 injuries/1000 AE (95% CI 9.06 to 10.62). Statistically significant associations were found between upper limb injuries and level of play; and between shoulder injuries and playing position (p<0.05). No association was found between upper limb and shoulder injuries and study year. The overall upper limb IIR decreased as the level of play increased; 10.74 upper limb injuries/1000 AE (95% CI 9.93 to 11.56) in Colts to 6.07 upper limb injuries/1000 AE (95% CI 5.46 to 6.69) in Elite. Conclusions The upper limb IIR decreased as the level of play increased indicating that age, level of skill and playing experience may be risk factors for upper limb injury.

Shoulder injuries in elite rugby union football matches: Epidemiology and mechanisms

OBJECTIVES Shoulder injuries in rugby union football have been the focus of few in-depth studies, despite their frequency and severity. The studys objective was to describe the incidence, patterns and mechanisms of shoulder injuries in rugby. DESIGN Prospective cohort study of shoulder injury incidence and retrospective case-series study of shoulder injury mechanisms. METHODS Data were collected from Super Rugby matches from 2005 to 2010 involving elite level adult male rugby players. RESULTS 7920 player participation hours and 100 shoulder injuries were recorded during 397 Super Rugby matches. The shoulder injury incidence rate was 13 per 1000 player hours (95% confidence interval 10-16). The mean number of days unavailable for selection due to these injuries was 37 (95% confidence interval 25-54). Tacklers sustained shoulder injuries at a higher rate than ball carriers (Rate Ratio=1.7 (95% confidence interval 0.5-5.3)). The most frequently reported injuries were those to the acromio-clavicular joint; dislocations resulted in the greatest amount of missed play. Using video analysis, 47 of the 100 shoulder injury events were successfully identified and analyzed. The main mechanisms of shoulder injury were contact with the ground with the shoulder/arm in horizontal adduction, flexion, and internal rotation; and impact to the lateral aspect of the shoulder with the elbow flexed and arm at the side. CONCLUSIONS Direct impact to the shoulder, either through player-to-player contact or contact with the ground, is the main cause of shoulder injury. Methods to reduce injury risk, such as shoulder pads and tackle skills, require consideration.

A Preliminary Study of Acceptable Load Carriage for Primary School Children

This study investigated the changes in Ground Reaction Forces, GRFs and trunk inclination among primary students when carrying heavy backpacks. A randomised controlled experimental study was conducted on seven boys aged between 9 and 11 years old with similar Body Mass Index. Observations were done when the boys were carrying school bags of 0 (as control), 10, 15 and 20% of their own body weight whilst normal walking. Data acquisition was carried out using force platforms and 3-D motion analysis system. A significant difference in Ground Reaction Forces at load of 20% of body weight was found. The vertical GRF increased almost three times when loads increased up to 20% of body weight compared to 10% of body weight. The anterior-posterior GRFs were asymmetrical when loads were increased. When carrying load of 15% of body weight, the subjects adopted a compensatory trunk inclination. If Ground Reaction Forces and trunk inclination are important as the criteria to determine the acceptable backpack loads for children, those loads should not exceed 15% of body weight.

Effects of toe-out and toe-in gait with varying walking speeds on knee joint mechanics and lower limb energetics

Toe-out/-in gait has been prescribed in reducing knee joint load to medial knee osteoarthritis patients. This study focused on the effects of toe-out/-in at different walking speeds on first peak knee adduction moment (fKAM), second peak KAM (sKAM), knee adduction angular impulse (KAAI), net mechanical work by lower limb as well as joint-level contribution to the total limb work during level walking. Gait analysis of 20 healthy young adults was done walking at pre-defined normal (1.18m/s), slow (0.85m/s) and fast (1.43m/s) walking speeds with straight-toe (natural), toe-out (15°>natural) and toe-in (15°<natural). Repeated measure ANOVA (p<0.05) with post-hoc Tukeys test was applied for statistical analysis. Toe-out gait increased fKAM at all walking speeds (highest at normal speed) while toe-in gait reduced fKAM at all speeds (highest at fast walking speed). Toeing-in reduced KAAI at all speeds while toeing-out affected KAAI only at normal speed. Increasing walking speed generally increased fKAM for all foot positions, but it did not affect sKAM considerably. Slowing down the speed, increased KAAI significantly at all foot positions except for toe-in. At slow walking speed, hip and knee joints were found to be major energy contributors for toe-in and toe-out respectively. At higher walking speeds, these contributions were switched. The ankle joint remained unaffected by changing walking speeds and foot progression angles. Toe-out/-in gait modifications affected knee joint kinetics and lower limb energetics at all walking speeds. However, their effects were inconsistent at different speeds. Therefore, walking speed should be taken into account when prescribing toe-out/-in gait.

Biomechanical and functional efficacy of knee sleeves: A literature review

BACKGROUND Knee sleeves are widely used for the symptomatic relief and subjective improvements of knee problems. To date, however, their biomechanical effects have not been well understood. OBJECTIVE To determine whether knee sleeves can significantly improve the biomechanical variables for knee problems. METHOD Systematic literature search was conducted on four online databases - PubMed, Web of Science, ScienceDirect and Springer Link - to find peer-reviewed and relevant scientific papers on knee sleeves published from January 2005 to January 2015. Study quality was assessed using the Structured Effectiveness Quality Evaluation Scale (SEQES). RESULTS Twenty studies on knee sleeves usage identified from the search were included in the review because of their heterogeneous scope of coverage. Twelve studies found significant improvement in gait parameters (3) and functional parameters (9), while eight studies did not find any significant effects of knee sleeves usage. CONCLUSION Most improvements were observed in: proprioception for healthy knees, gait and balance for osteoarthritic knees, and functional improvement of injured knees. This review suggests that knee sleeves can effect functional improvements to knee problems. However, further work is needed to confirm this hypothesis, due to the lack of homogeneity and rigor of existing studies.

A NEW PYLON MATERIALS IN TRANSTIBIAL PROSTHESIS: A PRELIMINARY STUDY

Prosthesis is used to provide an individual who has an amputated limb with the opportunity to perform functional tasks, particularly ambulation (walking). The basic components of these lower limb prostheses are the foot-ankle assembly, pylon (shank), socket and suspension system. The pylon, which commercially made from Stainless Steel or Titanium is used to connect the socket to the ankle-foot assembly. Today, transtibial amputees have an equal number of options available in the market to fit sprinting, skiing, golf and swimming sport. However, these high-tech prostheses can cost several thousand dollars in the West and amputees from low-income countries just could not afford to buy them. Referring to the ISPO consensus conference on appropiate technology in developing countries 1995, most rehabilitation research has targeted low cost foot-ankle assemblies 1. However, in this study, the commercial pylon (shank) will be replaced by using the bamboo.

Combined effects of knee brace, laterally wedged insoles, and toe-out gait on knee adduction moment and fall risk in moderate medial knee osteoarthritis patients:

Background: Knee osteoarthritis is a major contributor to the global burden of disease. There is a need of reducing knee joint load and to improve balance and physical function among knee osteoarthritis patients. Objectives: To test the hypothesis that toe-out gait will reduce second peak knee adduction moment further and increase fall risk when combined with knee brace and laterally wedged insole in knee osteoarthritis patients. Study design: Single visit study with repeated measures. Methods: First and second peak knee adduction moments, fall risk and comfort level. First and second peak knee adduction moments were determined from three-dimensional gait analysis, completed under six randomized conditions: (1) natural, (2) knee brace, (3) knee brace + toe-out gait, (4) laterally wedged insole, (5) laterally wedged insole + toe-out gait, and (6) knee brace + laterally wedged insole + toe-out gait. Fall risk was assessed by Biodex Balance System using three randomized stability settings: (1) static, (2) moderate dynamic setting (FR12), and (3) high dynamic setting (FR8). Results: The reduction in first peak knee adduction moment and second peak knee adduction moment was greatest (7.16% and 25.55%, respectively) when toe-out gait combine with knee brace and laterally wedged insole. Significant increase in fall risk was observed with knee brace + laterally wedged insole + toe-out gait (42.85%) at FR12. Similar significant balance reductions were found at FR8 condition for knee brace + toe-out gait (35.71%), laterally wedged insole + toe-out gait (28.57%), and knee brace + laterally wedged insole + toe-out gait (50%) as compared to natural. However, knee brace decreased fall risk at FR12 by 28.57%. Conclusion: There is a synergistic effect of toe-out when combined with knee brace and laterally wedged insole concurrently in second peak knee adduction moment reduction but with a greater degree of fall risk. Simultaneous use of conservative treatments also decreases comfort level. Clinical relevance Patients with mild and moderate knee osteoarthritis are usually prescribed conservative treatment techniques. This study will provide an insight whether or not a combination of these techniques have a synergistic effect in reducing knee joint load.

Effects of different foot progression angles and platform settings on postural stability and fall risk in healthy and medial knee osteoarthritic adults

This study aims to investigate the effects of varying toe angles at different platform settings on Overall Stability Index of postural stability and fall risk using Biodex Balance System in healthy participants and medial knee osteoarthritis patients. Biodex Balance System was employed to measure postural stability and fall risk at different foot progression angles (ranging from −20° to 40°, with 10° increments) on 20 healthy (control group) and 20 knee osteoarthritis patients (osteoarthritis group) randomly (age: 59.50 ± 7.33 years and 61.50 ± 8.63 years; body mass: 69.95 ± 9.86 kg and 70.45 ± 8.80 kg). Platform settings used were (1) static, (2) postural stability dynamic level 8 (PS8), (3) fall risk levels 12 to 8 (FR12) and (4) fall risk levels 8 to 2 (FR8). Data from the tests were analysed using three-way mixed repeated measures analysis of variance. The participant group, platform settings and toe angles all had a significant main effect on balance (p ≤ 0.02). Platform settings had a significant interaction effect with participant group F(3, 144) = 6.97, p < 0.01 and toe angles F(21, 798) = 2.83, p < 0.01. Non-significant interactions were found for group × toe angles, F(7, 266) = 0.89, p = 0.50, and for group × toe angles × settings, F(21, 798) = 1.07, p = 0.36. The medial knee osteoarthritis group has a poorer postural stability and increased fall risk as compared to the healthy group. Changing platform settings has a more pronounced effect on balance in knee osteoarthritis group than in healthy participants. Changing toe angles produced similar effects in both the participant groups, with decreased stability and increased fall risk at extreme toe-in and toe-out angles.

Combined effects of knee brace, laterally wedged insoles and toe-in gait on knee adduction moment and balance in moderate medial knee osteoarthritis patients

OBJECTIVE To test the hypothesis that toe-in gait (TI) will further reduce first peak (Knee Adduction Moment) KAM and decrease balance when combined with a knee brace (KB) and laterally wedged insoles (LWI) in medial knee osteoarthritis (kOA) patients. PARTICIPANTS Twenty patients with bilateral symptomatic medial kOA. INTERVENTIONS 4-point leverage-based KB, full-length LWI with 5° inclination and toe-in gait (TI). MAIN OUTCOME MEASURES First and second peak knee adduction moment (fKAM and sKAM respectively), balance and pain. METHODS The fKAM and sKAM were determined from 3-dimensional gait analysis with six randomized conditions: (1) N (without any intervention), (2) KB, (3) KB + TI, (4) LWI, (5) LWI + TI, (6) KB + LWI + TI. Balance was assessed by Biodex Balance System using three stability settings, (i) Static (ii) Moderate dynamic setting for fall risk (FR12) and (iii) High dynamic setting for fall risk (FR8). RESULTS The reduction in fKAM and sKAM was greatest (19.75% and 12%) when TI was combined with KB and LWI respectively. No change in balance was observed when TI combined with KB, and LWI and when used concurrently with both the orthosis at static and FR12 conditions. Significant balance reduction was found at FR8 for KB + TI (22.22%), and KB + LWI + TI (35.71%). Pain increased significantly for KB (258%), KB + TI (305%), LWI + TI (210%) and KB + LWI + TI (316%). LWI showed no effect on pain. CONCLUSIONS There is a synergistic effect of TI when combined with KB and LWI concurrently in sKAM reduction. However, the concurrent use of TI, KB and LWI decreases balance and pain as assessed on a highly dynamic platform.