Epidemiologic data suggest 25% to 75% of all runners experience an overuse injury each year. Commonly cited biomechanical factors related to overuse injuries such as Achilles tendinopathy or medial tibial stress syndrome include excessive amounts or velocities of foot pronation. However, there is conflicting evidence in the literature supporting this theory. An alternative hypothesis suggests it is not necessarily the amount or velocity of pronation which is important for injury development; rather it is the duration the foot remains in a pronated position throughout stance that is the important variable. This project examined this hypothesis by first identifying biomechanical markers of prolonged pronation. Second, it assessed whether individuals currently symptomatic with injuries typically attributed to excessive pronation instead demonstrate the biomechanical markers of prolonged pronation. Finally, musculoskeletal modeling techniques were used to examine musculotendinous kinematics in injured and healthy runners, as well as healthy runners with prolonged pronation. The results suggest the two most robust measures for identifying individuals with prolonged pronation are the period of pronation and the eversion of the rear foot at heel off. Individuals with prolonged pronation can also be identified with a set of clinically feasible measures including higher standing tibia varus angles, reduced static hip internal rotation range of motion, and increased hip internal rotation during stance phase. Finally, individuals with prolonged pronation display a more medially located center of pressure trajectory during stance. Compared to healthy controls, individuals currently symptomatic with Achilles tendinopathy or medial tibial stress syndrome did not differ in the amount or velocity of pronation. However, they did demonstrate the biomechanical markers of prolonged pronation. Injured individuals also demonstrated greater average musculotendinous percent elongation than healthy controls, especially through mid and late stance. Currently healthy individuals demonstrating prolonged pronation exhibited musculotendinous percent elongations intermediate to the healthy and injured groups. As a whole, the results from this study suggest prolonged pronation may play a role in the development of common overuse running injuries. It is suggested future studies on injury mechanisms consider pronation duration as an important variable to examine. This dissertation includes unpublished co-authored material.

This thesis is the culmination of a series of studies designed to improve the management of musculoskeletal (MSK) injury in an infantry training centre (ITC Catterick, UK). The overall aim of this thesis is to develop and evaluate a management strategy for MSK injury during Combat Infantryman’s Courses (CIC) training. Included is an epidemiological study of MSK injuries in the British Army (Study1), a risk factor model for MTSS (Study 2) and two randomised controlled trials (RCTs) in which the effects of prevention (Study 3) and rehabilitation interventions (Study 4) were examined. The aim of Study 1 was to quantify incidence, type and impact of the MSK injuries during military CIC training (26 weeks). Over a two year period (April 2006 -March 2008), 6608 British infantry CIC trainees completed an informed consent form to take part in this study. A prospective epidemiological study was conducted. Data for the injuries were reported according to: onset, anatomical location, diagnosis and regiment-specific incidence, week and months, impact and occupational outcome. It was clearly demonstrated that MSK injuries are a substantial burden to the British Army. Injury rate was 48.65% and overuse injury was significantly higher than acute and recurrence. Most overuse injuries occurred in the lower limb (82.34%) and were more frequent (p <0.01) in the first phase of training (Weeks 0-13). One third of the recruits (33%) were discharged prior to completion of training. A further 15% (n=991) were removed from training for further rehabilitation. Rehabilitation time ranged from 21 to 168 days and 12% of total training time was lost due to injury (equivalent to 155,403 days of training). Owing to its high severity index, medial tibial stress syndrome (MTSS) is argued to be the most impactful of these injuries despite only being second most frequent. Implications for practice and research (Study 1): MSK injuries are a significant burden to the British Army and strategies to improve prevention and treatment need to be explored. An initial focus on MTSS is warranted. In order to develop interventions for Studies 3 and 4 it is necessary to identify those risk factors for developing MTSS. The aim of Study 2 was to determine prospectively whether gait biomechanics and/or lifestyle factors can identify those at risk of developing MTSS. Again, British Infantry male recruits (n = 468) were selected for the study. Based on a review of the literature of known risk factors for MSK injury, plantar pressure variables, lifestyle factors comprising smoking habits and aerobic fitness as measured by a 1.5 mile timed-run were collected on the first day of training. A logistic regression model for membership of the MTSS and non-MTSS groups showed that an imbalance in foot pressure (heel rotation = pressure on the medial heel minus pressure on the lateral heel) was the primary risk factor for MTSS. Low aerobic fitness and smoking habit were also important, but were additive risk factors for MTSS. The logistic regression model combining all three risk factors was capable of predicting 96.9% of the non-injured group and 67.5% of the MTSS group with an overall accuracy of 87.7%. Implications for practice and research (Study 2): Foot pronation, as measure by heel rotation, is a primary risk factor for MTSS. Previous studies have shown that gait retraining can change risk factors for injury. The aim of Study 3 was to examine the effectiveness of gait retraining on reducing risk factors associated with MTSS and on reducing the incidence of MTSS during the subsequent 26 week training period. British Infantry recruits (n = 450) volunteered for the study and baseline plantar pressure variables were recorded on the first day of training. Based on the findings of Study 2, those with abnormal foot pronation at baseline (n = 134, age 20.1 ± 2.03 years; height 167 ±1.4 cm; body mass 67 ± 2.4 kg) were randomly allocated to an intervention (n = 83) or control group (n = 83). The intervention group undertook a gait retraining program which included targeted exercises three times a week and biofeedback on risk factors once per week. Both groups continued with the CIC training concurrently. Injury diagnoses over the 26 week training regimen were made by physicians who were blinded to the study. Post-measures of plantar pressure were recorded at 26 weeks. There was a significant reduction in the pronation (p <0.001) and overall difference survival function between MTSS and non-MTSS (Log rank test X2 = 6.12, p = 0.013). The absolute risk reduction was 60% in the intervention group. Implications for practice and research (Study 3): Gait retraining can reduce risk factors and incidence of MTSS injury. Based on such positive findings for the prevention of MTSS in Study 3, it was hypothesised that gait retraining may also have potential for the rehabilitation of MTSS. The aim of Study 4 was to examine the effectiveness of a gait retraining on plantar pressure variables, pain intensity and time spent in rehabilitation due to MTSS. Recruits diagnosed with MTSS but not responding to current treatment were eligible for this study (n = 66, age 20.85 ± 2.03 years; height 167 ±1.4 cm; body mass 67 ± 2.4 kg). The participants were randomly allocated to an intervention (n = 32) or control group (n = 34). In order to overcome the debilitating pain suffered by MTSS patients during exercise, the intervention group received a corticosteroid injection prior to the gait retraining programme. The control group continued with the current rehabilitation programme. There were significant improvements in terms of time to reach peak heel rotation (p<0.001), pain intensity (p<0.001) and positive occupational outcome in the intervention group (p<0.019). Implications for practice and research (Study 4): A combined corticosteroid-exercise intervention is beneficial in normalising plantar pressure, reducing rehabilitation times, pain intensity and occupational outcome of MTSS.

With the general increase in Rugby union's popularity the past decade, there has been an increase in sport injuries, both from acute and overuse trauma. Approximately half of all sport injuries may be attributed to overuse or repetitive micro trauma rather than a single traumatic event. Although very few overuse injuries have an established aetiology, the fact that over 80% of these injuries occurs at or below the knee suggests that there may be some common mechanisms in the aetiology. It could only be stated with certainty that the aetiology of these injuries is multifactorial and diverse, with both extrinsic and intrinsic factors contributing. Many intrinsic factors (personal) predispose athletes to develop overuse injuries. Intervention of intrinsic injury risk factors is more problematic, as intrinsic risk factors are often difficult to examine and even more difficult to rehabilitate than external factors. Extrinsic risk factors (environmental) that are independent of the injured person can be influenced through the intervention of the extrinsic factors. Main attention should be paid not to the treatment of the site of injury but to the possible cause of the symptoms. It is therefore vital that coaches and medical teams have a complete understanding of the incidence, nature, severity, and causes of injuries in order to review the adequacy of their injury prevention, treatment and rehabilitation. The objectives of this study were to determine the effect of selected anthropometric parameters, biomechanical malalignment and flexibility on the prevalence of Medial tibial stress syndrome (MTSS) in U/19 university rugby players of the 2006 season of the North-West University (NWU) Rugby Institute (RI). A prospective once-off subject availability study was performed that included U/19 rugby union players of the RI of the NWU (n=91). Selected biomechanical and anthropometrical assessments were made. Biomechanical and anthropometrical assessments were preformed on all subjects before the start of the season. All existing injuries were recorded by means of an injury history questionnaire. Descriptive statistics (e.g. mean and standard deviations) and contingency tables were used to analyse the data. Effect sizes were used to decide on the practical significance of the findings. A cut-off point of 0.8 (large effect) was set for practical significance of differences between means. Players with MTSS had a wider Bi-iliocristal width than those without MTSS. There were leg length differences for both players with and without MTSS for Hiospinale, Trochanterion-Tibiale lateral and Tibial lateral length. Iliospinale- and Trochanterion-Tibiale lateral length differences presented with the largest length difference. Iliospinale, Trochanterion-Tibiale lateral and Tibial lateral length difference had a small effect. Only Bi-iliocristal width presented with a medium effect. Hamstrings, Gastrocnemius and Plantaris as well as Soleus and Popliteus flexibility of players without MTSS were tighter than those of players who suffered from MTSS. Only Hamstring tightness had a small effect. Gastrocnemius and Plantaris as well as Soleus and Popliteus presented with a medium effect. Players without MTSS had a more flexible TFL on their right side. All the other flexibility measurements of the Thomas test presented that players without MTSS had a more inflexible profile. Effect size was not analysed because of the small sample sizes in some of the cells. Players without MTSS presented with an overall more inflexible profile than those with MTSS. More players without MTSS supinated at heel contact on both their feet, compared to the players with MTSS. Players without MTSS supinated more on both their feet during mid stance. A small percentage of players with and without MTSS supinated during the propulsion phase. More players without MTSS had a neutral right foot mid stance compared to players with MTSS who had a more neutral mid stance on their right foot. Players with MTSS pronated more with both their feet during propulsion. Players with MTSS pronated mostly during the propulsion phase and mostly had flatter and higher arched feet than players without MTSS. More players with MTSS had a light flat foot, flat foot as well as a high arched foot than players without MTSS. Most of the players with MTSS had normal right arched foot type. None of the players with MTSS had either a light high right foot or a high arched left foot. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

With the general increase in Rugby union's popularity the past decade, there has been an increase in sport injuries, both from acute and overuse trauma. Approximately half of all sport injuries may be attributed to overuse or repetitive micro trauma rather than a single traumatic event. Although very few overuse injuries have an established aetiology, the fact that over 80% of these injuries occurs at or below the knee suggests that there may be some common mechanisms in the aetiology. It could only be stated with certainty that the aetiology of these injuries is multifactorial and diverse, with both extrinsic and intrinsic factors contributing. Many intrinsic factors (personal) predispose athletes to develop overuse injuries. Intervention of intrinsic injury risk factors is more problematic, as intrinsic risk factors are often difficult to examine and even more difficult to rehabilitate than external factors. Extrinsic risk factors (environmental) that are independent of the injured person can be influenced through the intervention of the extrinsic factors. Main attention should be paid not to the treatment of the site of injury but to the possible cause of the symptoms. It is therefore vital that coaches and medical teams have a complete understanding of the incidence, nature, severity, and causes of injuries in order to review the adequacy of their injury prevention, treatment and rehabilitation. The objectives of this study were to determine the effect of selected anthropometric parameters, biomechanical malalignment and flexibility on the prevalence of Medial tibial stress syndrome (MTSS) in U/19 university rugby players of the 2006 season of the North-West University (NWU) Rugby Institute (RI). A prospective once-off subject availability study was performed that included U/19 rugby union players of the RI of the NWU (n=91). Selected biomechanical and anthropometrical assessments were made. Biomechanical and anthropometrical assessments were preformed on all subjects before the start of the season. All existing injuries were recorded by means of an injury history questionnaire. Descriptive statistics (e.g. mean and standard deviations) and contingency tables were used to analyse the data. Effect sizes were used to decide on the practical significance of the findings. A cut-off point of 0.8 (large effect) was set for practical significance of differences between means. Players with MTSS had a wider Bi-iliocristal width than those without MTSS. There were leg length differences for both players with and without MTSS for Hiospinale, Trochanterion-Tibiale lateral and Tibial lateral length. Iliospinale- and Trochanterion-Tibiale lateral length differences presented with the largest length difference. Iliospinale, Trochanterion-Tibiale lateral and Tibial lateral length difference had a small effect. Only Bi-iliocristal width presented with a medium effect. Hamstrings, Gastrocnemius and Plantaris as well as Soleus and Popliteus flexibility of players without MTSS were tighter than those of players who suffered from MTSS. Only Hamstring tightness had a small effect. Gastrocnemius and Plantaris as well as Soleus and Popliteus presented with a medium effect. Players without MTSS had a more flexible TFL on their right side. All the other flexibility measurements of the Thomas test presented that players without MTSS had a more inflexible profile. Effect size was not analysed because of the small sample sizes in some of the cells. Players without MTSS presented with an overall more inflexible profile than those with MTSS. More players without MTSS supinated at heel contact on both their feet, compared to the players with MTSS. Players without MTSS supinated more on both their feet during mid stance. A small percentage of players with and without MTSS supinated during the propulsion phase. More players without MTSS had a neutral right foot mid stance compared to players with MTSS who had a more neutral mid stance on their right foot. Players with MTSS pronated more with both their feet during propulsion. Players with MTSS pronated mostly during the propulsion phase and mostly had flatter and higher arched feet than players without MTSS. More players with MTSS had a light flat foot, flat foot as well as a high arched foot than players without MTSS. Most of the players with MTSS had normal right arched foot type. None of the players with MTSS had either a light high right foot or a high arched left foot. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

The identification of risk factors associated with overuse injuries, specifically Medial Tibial Stress Syndrome (MTSS) and Tibial Stress Fractures (TSF), may help professionals with management and prevention of these injuries. The purpose of this study was to identify risk factors associated with MTSS and TSF in female intercollegiate athletes. This study used a mulitifactorial, prospective design for 13-26 weeks. Thirty-nine Division I intercollegiate female student-athletes in volleyball, soccer, and track were examined. Anatomical, physiological (eating disorder and menstrual history), and training (duration and recovery time) characteristics were examined as possible risk factors. Only two injuries were reported during the study; therefore, analysis for risk factors was not possible. Descriptive statistics for the dependent variables were calculated, and comparisons across sport were performed. Differences in leg length values and dorsiflexion ROM were observed across sports. No conclusions could be drawn regarding possible risk factors for MTSS and TSF in this population.

Introduction: Foot over-pronation, attributable to Tibialis Posterior (TP) muscle weakness, is a possible cause of medial tibial stress syndrome (MTSS)3. Taping may provide a viable alternative for a dysfunctional TP and its associated navicular drop (ND). The most commonly used Augmented LowDye (ALD) technique has shown to prevent ND, but is time- and cost- intensive, leading us to explore an alternative technique. The purpose of this study was to assess the effectiveness of a new, anti-pronation (AP) taping technique, as compared to the ALD, to (a) reduce or prevent ND and (b) cause a lateral shift in the center of pressure (COP) measures. Methods: This is a 2 (tape techniques) by 3 (time: baseline, tape/pre-exercise, and tape/post-exercise) controlled laboratory study design. Twenty symptomatic (ND >/= 10 mm) college-age subjects were prepared with one of the 2 tape techniques and/or control and performed the ND test three times and walk across a pressure mat five times. Then the participants fatigued the tape by walking on a treadmill for 15 minutes at 3.0 mph at 0% grade and ND and pressure mat readings were recorded again. A within and within ANOVA allowed for the examination of between and within comparisons and a functional analysis (lateral shift as a function of time) on the mat-generated data were done p<.05. Results: Results revealed significant differences across times, and a times-by-tape technique interaction but differences between tape techniques were not significant. M and SD and indicate that while both taping techniques reduced ND, only the AP technique was significantly different (HSDTukey (3,76)=1.44, p<.01) for every comparison other than AP pre-exercise, the mean lateral shift for the treatment was not significantly different from the control across any part of the normalized stance phase, but was significantly lower than the control in the 30-90% interval in the AP pre-exercise. Discussion: The AP technique not only controlled ND but also resulted in an increase in lateral excursion of the COP line during that portion of the stance phase associated with the structures and functions of the TP. Both techniques can be appropriately used but that the AP can be used with more confidence in its effectiveness. The MatScan has allowed examination of forefoot pronation in the horizontal plane, not just the vertical plane, yielding a more holistic analysis of forefoot pronation. Being able to analyze data in a functional fashion (i.e., lateral shift as a function of time) could allow researchers greater insights to the complex relationships between biomechanical movement and appropriate interventions.

Introduction: The New Balance Core Low Cut Sock (New Balance Athletic Shoe, Inc. · Boston, MA United States) is one of many arch support socks out in the market. These socks have an elastic portion, called a Stability Fit Arch Support & Hold technology, which has been incorporated into the arch area of the sock. The company makes the following claim that the socks provide, "Gentle compression to support the arch, relieving arch-related pain and discomfort."1 If these socks do provide adequate arch support, then they would allow individuals the ability to have an inexpensive method of arch support that is easy to apply and use. The purpose of this study is to test the effectiveness of these socks in (a) navicular drop (b) static pressure insole pressure profiles and (c) dynamic (walking and running) pressure insole pressure profiles. Methods: Eighteen symptomatic, college age (age 18-26) subjects were used in this study (seven male, eleven female), with symptomatic being defined as a navicular drop greater than or equal to 10 mm. Measurements were collected for both the navicular drop, and F-Scan insole data, for both static and dynamic stance. For walking and running trials, heel strike and toe off were identified by the Tekscan System and COP excursion coordinates evaluated throughout the stance phase. The COP coordinates were exported then compared over the stance phase. A series of functional analyses was used to assess the between group differences. A paired t-test was used to assess the within group differences. Results: Results indicate that the arch support socks were not significantly different from the control (regular socks) along any part of the foot strike (95% confidence) in any of the conditions (standing, walking or running). Results from the paired t-test revealed no significant differences in navicular drop between sock types (p = .379). Discussion: This study found that the elastic band in the New Balance socks did not provide increased support to the medial arch of the foot compared to the control sock in either the navicular drop paired t-test or the functional analysis of the static and dynamic data. The authors could not find any other comparable study on these kinds of socks. Compared to other reports, using both orthotic inserts and tape, ND was reduced, unlike the results found in the present study. 2 Our data are inconsistent with the idea that increased elastic support to the midfoot by these socks provides significant arch support. The authors would suggest another form of arch support such as orthotics or taping to aid on arch support rather than these socks.

Medial tibial stress syndrome (MTSS) is a stress and overuse injury that presents as pain on the medial aspect of the lower two-thirds of the tibia. It is most often caused by repetitive actions on hard surfaces such as running, marching, and dancing. Individuals most affected by MTSS are runners, members of the military, dancers, and athletes that play soccer, volleyball and basketball. While MTSS has a relatively standard presentation of pain on the medial aspect of the tibia, it can occasionally be mistaken for other injuries such as stress fractures or compartment syndrome. If a diagnosis is unsure, methods such as x-ray, bone-scan, and MRI can be utilized to better obtain the correct diagnosis. A variety of treatments exist for MTSS including, ice, massage, muscle strengthening, and rest. A combination of these various techniques is most often what is employed. In this study, the effectiveness of a set of resistance ankle exercises in combination with ice and massage was tested and compared to that of ice and massage alone. The hypothesis was that athletes receiving the exercises as part of their treatment, in addition to the icing and massaging, would have a greater decrease in pain from MTSS than athletes just receiving ice and massage as treatment. The exercises would strengthen the muscles of the lower leg that, when weak, can contribute to the development of MTSS. Results indicated that the exercises yielded a more significant decrease in pain from MTSS than ice and massage alone.