Bryce Dyer

The design of lower‐limb sports prostheses: fair inclusion in disability sport

Within lower‐limb disability running, the design of the prosthesis has shifted from being a tool for restoring function to one of enabling athletes to perform to near non‐disabled standards. This paper examines the background to this development. The authors argue that the impact of technology on the design of prostheses is likely to affect athletes’ abilities and unfairly advantage those who are able to access the most recent innovations. It is shown that historically in the case of lower‐limb sports prostheses, some variation in their performance is evident. The sports legislation does not allow for this difference. It is indicated that these observations are of concern to the sports stakeholders and therefore warrants further attention. It is suggested that the full understanding of the prostheses contribution may never be known. The authors propose a synthesis of quantitative performance data and a qualitatively obtained code of values to help police these concerns.

Performance enhancement of bi-lateral lower-limb amputees in the latter phases of running events: an initial investigation

Current methods of evaluating the performance of a runner using an energy return prosthesis often rely on a physiological methodology, making the differentiation between the contributions from the biological and the prosthetic elements of the below-knee amputee athlete difficult. In this paper a series of mass and composite foot systems were used to evaluate the effect that gravity, mass, stiffness and inertia have on the dynamic characteristics of a prosthesis. It is demonstrated that if the natural characteristics of a system are identified and synchronised with the physiological gait behaviour of a runner, performance enhancement can occur, resulting in a faster take off speed and in storing extra energy in the system that can later be recovered. Therefore, a bi-lateral amputee athlete with near symmetrical gait can recover the stored energy during the steady state or latter phases of a running event.

Modal analysis of composite prosthetic energy-storing-and-returning feet: an initial investigation

The desire of individuals with a lower-limb amputation to participate in sports, coupled with the high demands of athletics, has resulted in the development of energy-storing-and-returning feet, capable of storing energy during stance and returning it to the individual in late stance to assist in forward propulsion. However, little attention has been paid to date to advance the understanding of their dynamic characteristics (natural frequencies, mode shapes and damping) during running. The evaluation of such parameters is now urgently required, as the use of energy-storing-and-returning feet is now being investigated through legal and justice systems to determine participation of amputee athletes using them at the Olympic Games. This paper presents a study of the dynamic characteristics of two commercially available Elite Blade composite feet (solid and split foot). A full modal analysis of the feet was conducted with varying masses attached to them, representing different body masses. The study showed that natural frequencies close to typical running step frequency can be achieved with simple control of the mass or stiffness. It was concluded that further study of the dynamic characteristics could result in a significant change in the design, development and the attitude towards the use of composite prosthetic feet. This initial study has highlighted the key questions that need to be answered to fully understand the dynamic characteristics and inform designers on how to tune a foot to match an amputee’s gait and body condition.

The controversy of sports technology: a systematic review

Changes or introductions of technology or equipment can affect how a sport is played or influence its performances. This article conducted a systematic review of peer-reviewed literature to identify any case studies of controversial events surrounding the implementation or use of sports technology. 56 articles were identified that highlighted 31 different case studies found over a three decade time period. Thematic analysis revealed six distinctive themes when reviewing the articles. Whilst the sport of golf had the highest number of case studies, it was found that a significant level of attention had been recorded in the cases of Oscar Pistorius use of prosthetic legs in athletics and the use of full length swimsuits in swimming. The trend surrounding the number of articles was shown to be initially intermittent but saw a peak period from 2008 to 2010. However, the frequency of such articles since this peak has been more consistent. It is proposed that long periods of time without intervention or resolution by a governing body often increases the peer-reviewed attention paid to such cases in examples such as those identified in this systematic review.

Sprinting with an amputation: Some race-based lower-limb step observations

Background: T44 sprinting with an amputation is still in a state of relative infancy. Future scope for athletic training and prosthetic limb development may be assisted with a better understanding of information derived from T44 athletes when under race-based conditions. Objectives: To investigate the behaviour of step count and step frequency when under competitive conditions. Study design: The study comprises two elements: (1) a video-based analysis of race-based limb-to-limb symmetry and (2) a video-based analysis of race-based step count. Methods: Video analysis of several major events from 1996–2012 are assessed for step count and step limb-to-limb symmetry characteristics. Results: The video analysis highlights limb-to-limb imbalances greater than those indicated in the previous literature. A low step count is determined to be desirable for success in the 100-m event. Conclusion: Future analysis of athletes with a lower-limb amputation would be worthwhile when placed under race-based conditions as the limb-to-limb behaviour is more exaggerated than those seen in typical studies held within a laboratory setting. The within-event behaviour of step counts requires further investigation to establish where these take place or whether it is a cumulative step length issue. Clinical relevance This article increases the understanding of the race-based behaviour of amputee athletes and provides more information to contribute to any discussions on the performance of lower-limb prostheses.

An Investigation Into the Measurement and Prediction of Mechanical Stiffness of Lower Limb Prostheses Used for Running

Two energy return prosthesis are subjected to three different statically applied loading methods. This initial study proposes that statically applied loading to a sport prosthesis using several controlled methods were statistically robust enough to derive a mechanical stiffness value. However, any predicted stiffness is drawn into question when allowing any movement of the distal end. This uncertainty will make any evaluation or prescription of lower limb prosthesis technology based upon their stiffness incorrect. In addition, the peak calculated stiffness at the expected bodyweight induced ground impact load of a runner is judged the most representative assessment method. This study attempts to build on previous research advocating the need to monitor the performance of prosthesis lower limb technology in disability sport.

The importance of aerodynamics for prosthetic limb design used by competitive cyclists with an amputation: An introduction

Background/Objectives: This study introduces the importance of the aerodynamics to prosthetic limb design for athletes with either a lower-limb or upper-limb amputation. Study design: The study comprises two elements: 1) An initial experiment investigating the stability of outdoor velodrome-based field tests, and 2) An experiment evaluating the application of outdoor velodrome aerodynamic field tests to detect small-scale changes in aerodynamic drag respective of prosthetic limb componentry changes. Methods: An outdoor field-testing method is used to detect small and repeatable changes in the aerodynamic drag of an able-bodied cyclist. These changes were made at levels typical of alterations in prosthetic componentry. The field-based test method of assessment is used at a smaller level of resolution than previously reported. Results: With a carefully applied protocol, the field test method proved to be statistically stable. The results of the field test experiments demonstrate a noticeable change in overall athlete performance. Aerodynamic refinement of artificial limbs is worthwhile for athletes looking to maximise their competitive performance. Conclusion: A field-testing method illustrates the importance of the aerodynamic optimisation of prosthetic limb components. The field-testing protocol undertaken in this study gives an accessible and affordable means of doing so by prosthetists and sports engineers. Clinical relevance Using simple and accessible field-testing methods, this exploratory experiment demonstrates how small changes to riders’ equipment, consummate of the scale of a small change in prosthetics componentry, can affect the performance of an athlete. Prosthetists should consider such opportunities for performance enhancement when possible.

The dynamic elastic response to impulse synchronisation of composite prosthetic energy storing and returning feet

In this research, it is proven that perfect synchronisation between the input impulse (human effort) and the ground reaction impulse/impact can result in a phenomenon called the dynamic elastic response to impulse synchronisation with favourable consequences to the behaviour of the energy storing and returning foot. An energy storing and returning composite prosthetic foot was first used in elite competition at the 1988 Paralympic Games. Since its introduction, the prostheses have proven to be a source of controversy. In 2008, it was concluded that the athletes who use such technology when running are in an advantageous position when compared to able-bodied athletes. However, these findings have since been disputed. There still remain unanswered questions regarding the level of contribution of energy storing and returning feet in the performance of amputee athletes. A series of investigations have previously been conducted to study the dynamic characteristics of a number of energy storing and returning composite prosthetic feet. It was found that if a sinusoidal input impulse, with a frequency close to one of the energy storing and returning feet’s natural frequencies, could be applied, it can make the energy storing and returning foot susceptible to resonance, which, in the case of bending mode, if sustained can lead to a gain in height or increased velocity.

Cycling with an amputation: A systematic review

Background: Cycling with any form of limb amputation has progressed from an activity of leisure or rehabilitation to elite level competition as part of the Paralympic Games programme. Objective: While it is often proposed that research into sport with an amputation can be extremely limited, this study intended to identify the volume, type and historical strategy in this area. Study design: This study comprises a documented systematic literature review of cycling undertaken with any form of limb amputation. Method: This study used four online search engines to identify relevant peer-reviewed literature. These included SPORTDiscus, CINAHL, Scopus and MEDLINE. Google Scholar was also used as a secondary source. The initial results were then subjected to a set of pre-defined inclusion criteria. The resulting publications were then analysed for content and thematic commonality. Results: The review identified 20 articles which met pre-defined inclusion criteria. The identified peer-reviewed publications were dated from the period 2004 to 2014. Conclusions: Three clear themes emerged from the historical research. There was both a paucity of peer-reviewed literature with respect to cycling with an amputation and the design of adaptive or assistive technology to replace limb loss. However, publications have been rising substantially over the last 5 years. Clinical relevance This review study established the historical strategy and content of cycling with an amputation and identified the existing research themes. This will assist in summarising the current level of knowledge and help signpost such work in the future.

Retinoblastoma: Identifying the Diagnostic Signs for Early Treatment

Retinoblastoma is a rare but significant cause of childhood eye cancer world-wide. The prognosis depends upon early diagnosis and treatment but also upon accurate classification of the tumours. Unilateral incidence is normally non-hereditary compared with bilateral incidence where secondary tumours are more common. Survivorship is much better for unilateral compared with bilateral and trilateral retinoblastoma. Early signs are important to detect and photography can assist in identifying no return of “red-eye” during flash photography and yellow appearance of the tumour. Treatment options are discussed together with new psycho-oncology approaches that address potential trauma in the survivor as well as in the family of the survivor.