Adaptive Running

Impaired muscle power

The muscles in the limbs or trunk are completely or partially paralyzed as a consequence of conditions such as spinal cord injury, polio, or spina bifida

Impaired passive range of movement

Range of movement in one or more joints is permanently reduced due to trauma, illness or congenital deficiency (e.g., conditions such as arthrogryposis or joint contracture resulting from trauma)

Limb deficiency

A total or partial absence of bones or joints, from birth, as a consequence of trauma (e.g., traumatic amputation) or illness (e.g., amputation due to cancer)

Ataxia

Lack of muscle coordination due to problems with the parts of the central nervous system that control movement and balance, typical of conditions such as traumatic brain injury and cerebral palsy

Athetosis

Repetitive and more or less continual involuntary movements caused by fluctuating muscle tone arising from problems in the central nervous system, typical of conditions such as cerebral palsy

Hypertonia

Abnormal increase in muscle tension with reduced ability of muscles to stretch and joint stiffness, slowness of movement, and poor postural adaptation and balance, due to problems in the central nervous system, typical of conditions such as cerebral palsy, traumatic brain injury, and stroke

Short stature

Standing height and limb length are reduced due to conditions such as achondroplasia and osteogenesis imperfecta

Leg length difference

Minimum of 7 cm leg length difference due to trauma, illness, or congenital conditions

Visual impairment

Vision is impacted by either an impairment of the eye structure, optical nerve/pathways or the part of the brain controlling vision (visual cortex)

Intellectual impairment

Limited intellectual functions and adaptive behavior, which must be diagnosed before the age of 18

Classification

To ensure fair and equal competition, a classification system is used to group athletes into sport classes based on impairment and activity limitations (Table 9.2) [3]. The aim of classification in IPC athletics is to minimize the impact of eligible impairments on the outcome of competition. According to the IPC, athletes with impairments that have a similar impact on sport performance will generally compete in the same sport class. The system ensures that athletes do not succeed simply because they have an impairment that causes less of a disadvantage than their competitors but because of their skill, determination, tactics, fitness, and preparation. In order to be classified, the participant must submit a copy of the IPC Medical Diagnostic Form and all relevant documentation that is completed by their physician. For athletes competing in road races, such as the Boston Marathon, there may be different classification systems used (Table 9.3) [4].

Table 9.2

IPC sport classification track/running events

	Athletes with visual impairment
T11–T13	Athletes in these classes have a visual impairment, which is severe enough to impact on sport
	Athletes with intellectual impairment
T20	Athletes in this class have an intellectual impairment that impacts on the activities of running (400 m—marathon)
	Wheelchair racing
T32–34	These athletes compete in a wheelchair typically secondary to coordination impairments including hypertonia, ataxia, and athetosis (i.e., cerebral palsy, head injury, or stroke)
T51	Athletes usually have decreased shoulder muscle power and difficulty straightening the elbows for a pushing action required for wheelchair racing propulsion. There is no muscle power in the trunk. Wheelchair propulsion is achieved with a pulling action using the elbow flexor and wrist extensor muscles
T52	Athletes use their shoulder, elbow, and wrist muscles for wheelchair propulsion. There is poor to full muscle power in the fingers with wasting of the intrinsic muscles of the hands. Muscle power in the trunk is typically absent
T53	Athletes typically have full function of the arms but no abdominal or lower spinal muscle activity (grade 0)
T54	Athletes have full upper muscle power in the arms and some to full muscle power in the trunk. Athletes may have some function in the legs
	Track running
T35–38	These athletes typically have coordination impairments including hypertonia, ataxia, and athetosis but are able to functionally run (i.e., cerebral palsy, head injury, or stroke)
T40–41	There are two classes depending on the body height of the athlete and the proportionality of the upper limbs. Athletes in classes T40 have a shorter stature than T41
T42	Athletes have a single above-knee amputation or impairments that are equivalent to an amputation above the knee
T43	Athletes have double below-knee amputations or impairments that are equivalent to a double below-knee amputations
T44	Athletes have a single below-knee amputation or impairments that are equivalent to a single below-knee amputation
T45	Athletes have double-arm amputations above or below the elbow or equivalent impairments
T46	Athletes have a single above- or below-elbow amputation or impairments that are equivalent to a single-arm amputation

Table 9.3

Boston Marathon wheelchair racing classifications

Quad class
Class 1	Have functional elbow flexors and wrist dorsiflexors. Have no functional elbow extensors or wrist palmar flexors. May have shoulder weakness
Class 2	Have functional elbow flexors and extensors, wrist dorsiflexors, and palmar flexors Have functional pectoral muscles. May have finger flexors and extensors
Open class
Class 3	Have normal or nearly normal upper-limb function. Have no abdominal muscle function. May have weak upper-spinal extension
Class 4	Have normal or nearly normal upper-limb function. Have no abdominal muscle function. May have weak upper-spinal extension

Equipment

Prostheses for Amputee Athletes

The prototypical prosthesis used by athletes for running and track and field is the “running blade (Fig. 9.1).” These are also known as energy, storing, and returning (ESR) prostheses or running-specific prostheses (RSP). Running prostheses are made from a carbon fiber polymer that is designed to store kinetic energy, similar to the way a spring functions. ESR prostheses are attached to the athlete using a socket, with liners and pads used to enhance fit and prevent skin breakdown. Sockets (Fig. 9.1) are created similarly for both athletic and non-athletic purposes, but sockets for athletes are commonly made of carbon fiber. This adds considerably to the cost but also improves durability and weight. ESR prostheses are designed for energy storage and propulsion. There are different designs to the ESR prostheses to allow for different distances and speeds of racing. There is no ankle joint or heel, making standing still with ESR prostheses difficult. Different surfaces can be attached to the bottom of the prosthesis for traction and improved wear. Athletes typically cut soles from running shoes and attach them to the prosthesis with glue or velcro. The Nike Sole is a shoe made specifically for attaching to running blades.

Fig. 9.1

The athlete in the figure is shown with his running blade attached to his custom-made socket. Photo courtesy of Lawall Prosthetics and Orthotics

The energy cost of ambulation and running with a prosthesis is greater than an able-bodied athlete, which can vary based on speed, cardiovascular fitness, level of amputation, reason for amputation, and the properties of the prosthesis itself. The running-specific ESR prostheses can lower heart rate during exercise and lower the total energy cost to the athlete, when compared to a typical prosthesis. There is considerable debate about whether ESR prostheses offer an unfair advantage to disabled athletes during competition against able-bodied athletes and among other limb-deficient athletes. There have been multiple studies on the subject, yet no consensus has been reached. Some have concluded that there is no physiological advantage when compared with non-amputee athletes [5, 6], while others feel that the use of an ESR prostheses does provide an advantage [7–9]. Of note, there is some evidence to suggest the energy cost of an individual running with an ESR prosthesis is very similar to an able-bodied athlete. The length of the running blades has also been identified as a potential area for an unfair advantage among limb-deficient athletes [10, 11]. The IPC has set rules related to the length of prosthetic limbs used in competition by dictating a maximum allowable standing height (MASH) for athletes with prosthesis, commonly referred to as the MASH rule. These rules should be referenced when a limb-deficient athlete is being fitted for a prosthesis that will be used for competitive purposes.

It is also important for close follow-up of the limb-deficient athlete to ensure proper fit of the socket and prosthesis. Athletes can often develop skin breakdown, residual limb swelling, and pain secondary to a poorly fitted socket creating pressure points, poor circulation, and shear forces on the residual stump. Typical prostheses can last several years, but a change in fit and wear on the other components can often necessitate a revision or replacement.

Racing Wheelchairs

Racing wheelchairs consist of two larger rear wheels and a single wheel up front. The front wheel is smaller in diameter and extends well in front of the seat elongating the chair (Fig. 9.2). This provides improved stability and shock absorbance at the expense of maneuverability. The athlete is generally placed in a kneeling position, suspended in a sling, though a seated position in the chair is possible as well. Appropriate padding is necessary to prevent shear force and pressure to the weight-bearing surfaces. The athlete is fit tightly into the wheelchair to increase stability [12]. Similar to most sport wheelchairs, the wheels are cambered. They use pneumatic tires and aim to be very lightweight, most often with frames constructed of aluminum. The majority of wheelchairs tend to be custom fit; however, many athletes begin with a basic racing wheelchair that meets IPC regulations. When making custom adjustments, careful consideration should be paid to the IPC rules so that eligibility of the chair is retained (Table 9.4) [13]. Athletes are allowed one-hand rim per wheel, and they must have the ability for hand-operated mechanical steering and braking; however, there is not any gearing allowed. The rear wheels are limited to 70 cm diameter and the smaller front wheel 50 cm.

Fig. 9.2

Susannah Scaroni is shown demonstrating wheelchair propulsion mechanics. Photo courtesy of New York road runners. 2016 United Airlines half marathon

Table 9.4

IPC rules: racing wheelchair

Rule 159 Para 1

The wheelchair shall have at least two large wheels and one small wheel.

Rule 159 Para 2

No part of the body of the chair may extend forwards beyond the hub of the front wheel and be wider than the inside of the hubs of the two rear wheels. The maximum height from the ground of the main body of the chair shall be 50 cm.

Rule 159 Para 3

The maximum diameter of the large wheel including the inflated tyre shall not exceed 70 cm. The maximum diameter of the small wheel including the inflated tyre shall not exceed 50 cm.

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