Functional Anatomy for Sport and Exercise

A Quick A-to-Z Reference

Clare Milner, Clare E. Milner

• Publisher: Routledge
• Year: 2019
• Print ISBN: 9781138541238
• eBook ISBN: 9780429575068
• Edition: 2
• Topic: Medicine
• Subtopic: Anatomy

Functional Anatomy for Sport and Exercise: A Quick A-to-Z Reference is the most user-friendly and accessible available reference to human musculoskeletal anatomy in its moving, active context. Fully updated and revised, the second edition features more illustrations to enhance student learning and an expanded hot topics section to highlight key areas of research in sport and exercise.

An accessible format makes it easy for students to locate clear, concise explanations and descriptions of anatomical structures, human movement terms and key concepts. Covering all major anatomical areas, the book includes:

• an A-to-Z guide to anatomical terms and concepts, from the head to the foot
• clear and detailed colour illustrations
• cross-referenced entries throughout
• hot topics discussed in more detail
• in sports examples discussed in more detail
• full references and suggested further reading

This book is an essential quick reference for undergraduate students in applied anatomy, functional anatomy, kinesiology, sport and exercise science, physical education, strength and conditioning, biomechanics and athletic training.

A to Z Entries

Ankle and Foot

The ankle and foot form a complex region containing many joints, which provide flexibility and enable the foot to adapt to its environment. This flexibility of the foot is essential because it is the point of contact between the ground and the body; it must be able to adapt to changes in terrain with minimum perturbation of the body system as a whole. The many bones and joints in the foot enable it to play multiple roles during activity; it is a flexible shock-attenuating structure during the early part of the stance phase of walking, and then becomes a rigid lever during push-off at the end of the stance phase. This change in dynamic function is achieved by activity of the invertor and evertor muscles of the foot (see ankle and foot – muscles). The invertors rotate the foot about its longitudinal axis from a flexible pronated position to a rigid supinated position and the evertors move the foot in the opposite direction (see ankle and foot – joints).

Owing to the foot’s position as the most distal segment in the body, the ankle and foot region is subjected to high loads, particularly during running and jumping activities. It is also subjected to large shear forces during cutting and other sidestep activities that occur in sports. As a result of these high loads and extreme positions, the ankle and foot are at high risk of injury (see In Sports 1). Additionally, injuries related to ankle and foot risk factors may manifest themselves higher up the kinetic chain – in the leg, knee, or hip. Overuse injuries related to foot and ankle structure and mechanics include plantar fasciitis, patellofemoral pain, and tibial stress fractures (see Hot Topic 1).

See also: ankle and foot – bones; ankle and foot – joints; ankle and foot – ligaments; ankle and foot – muscles; appendicular skeleton; foot arches.

Hot Topic 1 Tibial Stress Fracture in Runners

Stress fractures are a common overuse injury in runners. The most common site of a stress fracture is the tibia, typically in the region about a third of the way up the bone from the ankle. Female runners are at higher risk of tibial stress fracture than male runners, although it is unclear what the root cause of the difference is. A stress fracture develops when microscopic damage that is done to the bone during repeated loading accumulates over time. In runners, the bones are loaded every time the foot hits the ground. Bone constantly repairs itself and, in the healthy runner, the rate of repair or remodelling of the bone keeps pace with the rate of microdamage. This enables the bone to remain healthy and even become stronger over time to better withstand the repeated pavement pounding. However, if the balance is tipped and the rate of damage exceeds the rate of repair, microcracks in the bone eventually join up and a stress fracture occurs. A runner takes about 500 steps on each foot during every mile of running, each step subjects the body to a peak force of about three times the body’s weight. It is easy to appreciate the huge cumulative load experienced by the lower limbs over a period of weeks or months of running.

Numerous factors contribute to the development of a stress fracture and can tip the balance between damage and repair. Some of these can be modified to try and reduce the risk of injury. Structural factors such as the shape of the bone may predispose some runners to injury, but these cannot be altered. External factors related to training may also contribute and these can be altered to reduce the risk of injury. For example, the training programme may be a cause of injury if the weekly mileage (the total load on the body) is increased too quickly and tips the balance between damage and repair of the bone. Poor nutrition can also weaken the bone and reduce bone density, lowering the threshold at which loading will lead to stress fracture. This is a special concern among competitive distance runners who diet to reduce their body weight as much as possible and so restrict their intake of essential nutrients. The biomechanics of running (running technique), may also be an important factor. For example, some runners tend to hit the ground harder with every step, even after differences in weight are taken into consideration. These runners will have a higher total load on the body for every mile of running compared to those who are lighter on their feet.

After a tibial stress fracture, a period of rest and rehabilitation of up to 12 weeks is needed to allow the bone to remodel and repair itself. After sustaining a stress fracture once, the runner is quite likely to get another stress fracture in the future if they keep doing the same things they were before the injury. To avoid another stress fracture, special attention should be paid to factors such as the training programme, nutrition, and running biomechanics to correct any deficiencies which may put the athlete at increased risk of injury.

Further Reading

Warden, S. J., Davis, I. S. & Fredericson, M. (2014). Management and prevention of bone stress injuries in long-distance runners. Journal of Orthopaedic and Sports Physical Therapy, 44, 749–765.

In Sports 1 Chronic Ankle Instability

Ankle sprains or ‘rolling an ankle’ are a common injury in many sports. While either the medial or lateral ankle ligaments may be damaged, depending on the position of the foot and ankle at the time of injury, lateral ankle sprains are by far the most common. The injury occurs when the foot is forcibly supinated. The lateral ankle ligaments become taut in this position and, if the force is too great, one or more of them will be damaged or torn. The most common position at the time of injury is a supinated foot combined with a plantarflexed ankle. The ligament damage occurs from anterior to posterior, with the anterior talofibular ligament being torn first. The mechanism of injury is an external perturbation that places the foot and ankle in the at risk position combined with a sudden high force. For example, landing from a jump partially on an opponent’s foot in basketball or unexpectedly stepping off a high kerb while running. After the first ankle sprain, an athlete is at increased risk for spraining the ankle again. An athlete who experiences episodes of the ankle ‘giving way’ and typically suffers from multiple ankle sprains has chronic ankle instability. There are two main categories of chronic ankle instability: mechanical instability and functional instability. In mechanical ankle instability, the ligaments no longer restrain the ankle effectively – they may be elongated or even no longer intact and this allows the ankle to move into extreme positions. Alternatively, functional ankle instability is characterized by normal ligamentous restraint and instability is due to poor neuromuscular control. This may be attributed to loss of proprioception at the ankle leading to ineffective active muscular control of ankle position. Some athletes sprain their ankle and have no further symptoms – they are often referred to as ‘copers’ and there is a lot of research interest in understanding why and how they are able to cope with the injury. Athletes with chronic ankle instability often protect their ankle with rigid ankle braces that limit the amount of supination. Taping may also be used, but its effectiveness decreases with time as the tape loses adhesion to the skin due to sweating and limits prolonged activity. Rehabilitation programmes that aim to improve ankle proprioception and neuromuscular control may also help to reduce the risk of reinjury.

Further Reading

de Vries, J. S., Krips, R., Sierevelt, I. N., Blankevoort, L., & van Dijk, C. N. (2011). Interventions for treating chronic ankle instability. Cochrane Database of Systematic Reviews, 8. Art. No.: CD004124. DOI: 10.1002/14651858.CD004124.pub3.

Gribble, P. A., Bleakley, C. M., Caulfield, B. M., Docherty, C. L., Fourchet, F., Fong, D. T., … Delahunt, E. (2016). Evidence review for the 2016 International Ankle Consortium consensus statement on the prevalence, impact and long-term consequences of lateral ankle sprains. British Journal of Sports Medicine, 50(24), 1496. DOI: 10.1136/bjsports-2016-096189.

Ankle and Foot – Bones

The ankle and foot contain many bones and joints, giving the region high mobility. As the first point of contact between the body and the ground, this flexible segment enables the individual to adapt easily to changes in terrain. The bones of the ankle joint are those of the distal part of the leg – the tibia and fibula – and the talus. The 26 bones of the foot are the talus, calcaneus, navicular, cuboid, and the 3 cuneiforms – these are the tarsal bones – plus the 5 metatarsal bones and the 14 phalanges (Figure 5).

The talus is common to both the ankle and the foot, forming the distal part of the ankle joint and the proximal part of the subtalar joint. The distal ends of the tibia and fibula, the malleoli, form the proximal part of the ankle joint and can be used to approximate the ankle joint axis in vivo. The ankle joint axis passes just distal to the tips of the malleoli. According to Inman (1976), the ankle joint axis lies, on average, 5 mm distal to the tip of the medial malleolus, and 3 mm distal and 8 mm anterior to the tip of the lateral malleolus.

The bones of the foot and ankle are at risk of stress fracture, particularly in runners and military recruits. Stress fractures commonly occur in the navicular, the metatarsals and the distal third of the tibia. There is some evidence that the incidence of these overuse injuries is higher in those individuals who have narrower tibiae, since these bones are less able to resist the bending forces to which the leg is subjected when the foot contacts the ground on every stride. Furthermore, stress fractures occur twice as often in females than in males, although the reasons for this difference are unclear. Owing to the seriousness of stress fractures, which require several weeks rest from training and physical activity until the bone is healed, they are an important research topic for sports biomechanists and physiotherapists. Factors that are thought to be related to the risk of stress fracture include structural anatomy, functional me...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• List of Figures
• List of Tables
• List of Fundamentals
• List of A to Z Entries
• List of Hot Topics
• List of In Sports
• Acknowledgements
• Introduction
• Fundamentals
• A to Z Entries
• Bibliography
• Index