Prevention and Rehabilitation of Hamstring Injuries

Foreword
Conflicts of Interest
Acknowledgements
About the Book
Contents
About the Editors
1: Anatomy of the Hamstrings
	1.1	 Introduction
	1.2	 Proximal Insertions
		1.2.1	 Semimembranosus
		1.2.2	 Semitendinosus and Biceps Femoris Long Head
		1.2.3	 Biceps Femoris Short Head
	1.3	 Proximal Tendons and Musculotendinous Junctions
		1.3.1	 Semimembranosus
		1.3.2	 Semitendinosus and Biceps Femoris Long Head
		1.3.3	 Biceps Femoris Short Head
	1.4	 Architectural Characteristics of the Hamstrings
		1.4.1	 Muscle Size Measures
		1.4.2	 ACSA
		1.4.3	 PCSA
		1.4.4	 Volume
		1.4.5	 Fascicle Orientation and Length Measures
		1.4.6	 Within Muscle Variability in Architecture
			1.4.6.1	 Semimembranosus
			1.4.6.2	 Semitendinosus
			1.4.6.3	 Biceps Femoris Long Head
			1.4.6.4	 Biceps Femoris Short Head
	1.5	 Distal Tendons and Musculotendinous Junctions
		1.5.1	 Semimembranosus
		1.5.2	 Semitendinosus
		1.5.3	 Biceps Femoris
	1.6	 Distal Insertions
		1.6.1	 Semimembranosus
		1.6.2	 Semitendinosus
		1.6.3	 Biceps Femoris
	1.7	 Neurovascular Supply
		1.7.1	 Semimembranosus
		1.7.2	 Semitendinosus
		1.7.3	 Biceps Femoris Long Head
		1.7.4	 Biceps Femoris Short Head
	1.8	 Conclusion
	References
2: Basic Muscle Physiology in Relation to Hamstring Injury and Repair
	2.1	 Overview of Structural and Cellular Components Affected by Strain Injuries
		2.1.1	 Insights into the Basics of Muscle Strain Injuries
		2.1.2	 Development of the Myotendinous Junction and Its Adaptation to Loading and Unloading
		2.1.3	 Regeneration of Skeletal Muscle and the Connective Tissue
	2.2	 Hamstring Injury Sequelae
		2.2.1	 Structure and Cellular Components of Scar Tissue
		2.2.2	 The Inflammation-Fibrosis Link and Its Potential Role in Scar Formation After Strain Injuries
	2.3	 Proximal Hamstring Tendinopathy
		2.3.1	 Pathological Changes in Tendinopathy
		2.3.2	 Cellular Adaptations to Loading and Unloading in Tendon: How Is Mechanical Loading of Tendons Associated with Healing Processes?
	References
3: Hamstrings Biomechanics Related to Running
	3.1	 Introduction
	3.2	 Quantification of Hamstring Function
		3.2.1	 Hamstring Activation
		3.2.2	 Hamstring Kinematics
		3.2.3	 Hamstring Kinetics
	3.3	 Hamstring Function During Running
		3.3.1	 Swing Phase of the Stride Cycle
			3.3.1.1	 Hamstring Activation
			3.3.1.2	 Hamstring Kinematics
			3.3.1.3	 Hamstring Kinetics
		3.3.2	 Stance Phase of the Stride Cycle
			3.3.2.1	 Hamstring Activation
			3.3.2.2	 Hamstring Kinematics
			3.3.2.3	 Hamstring Kinetics
	3.4	 Effect of Prior Injury on Hamstring Function During Running
		3.4.1	 Muscle Activation
		3.4.2	 Kinematics
		3.4.3	 Kinetics
	3.5	 When Is the Critical Point in the Running Stride Cycle Where the Hamstrings Are Most Vulnerable to Injury?
	3.6	 Factors That Influence Biceps Femoris Long Head Strain During Sprinting
		3.6.1	 Muscle Coordination
		3.6.2	 Series Elastic Component Stiffness
		3.6.3	 Non-Uniform Strain Distribution
	3.7	 Conclusion
	References
4: Extrinsic and Intrinsic Risk Factors Associated with Hamstring Injury
	4.1	 Introduction
	4.2	 Interpreting Risk Factors
	4.3	 Intrinsic Risk Factors
		4.3.1	 Non-modifiable
			4.3.1.1	 Age
			4.3.1.2	 Previous Hamstring Injury
			4.3.1.3	 Previous History of Other Lower Leg Injuries
			4.3.1.4	 Ethnicity
			4.3.1.5	 Playing Position
		4.3.2	 Modifiable Risk Factors
			4.3.2.1	 Strength
				Eccentric Hamstring Strength
				Concentric and Isometric Hamstring Strength
				Asymmetry and Strength Ratios
				Strength-Endurance Measures
				Quadriceps Strength
				Other Lower Limb and Trunk Strength Measures
			4.3.2.2	 Architectural Factors
			4.3.2.3	 Power and Ballistic Function
			4.3.2.4	 Flexibility, Mobility, and Range of Motion
			4.3.2.5	 Muscle Activity and Motor Control
			4.3.2.6	 Muscle Fatigue
	4.4	 Extrinsic Risk Factors
		4.4.1	 Environmental Factors
		4.4.2	 Match Play, Sports Performance, Workload
		4.4.3	 Managing Injury Risk in the High-Performance Environment
	4.5	 Hamstring Injury Sequelae
	4.6	 Risk Factors for Proximal Hamstring Tendinopathy
	4.7	 Conclusion
	References
5: Neuromuscular Factors Related to Hamstring Muscle Function, Performance and Injury
	5.1	 Neural Factors Relating to Hamstring Muscle Function, Performance and Injury
		5.1.1	 Leg Muscle Strength, Rate of Force Development (RFD) and Sprint Performance
		5.1.2	 Eccentric Hamstring Strength and Sprint Performance
		5.1.3	 Neuromuscular Hamstring Activity, Sprint Performance and Risk of Muscle Strain Injury
		5.1.4	 Hamstring Strength, Endurance and Injury Risk
	5.2	 Intra- and Intermuscular Coordination
		5.2.1	 Intramuscular Coordination of the Hamstrings
		5.2.2	 Intermuscular Coordination: More Than Just a ‘One-Muscle Job’
	5.3	 Structural Factors Relating to Hamstring Muscle Function, Performance and Injury
		5.3.1	 Muscle Architecture and Function
		5.3.2	 Hamstring Fascicle Lengths, Pennation Angles and Injury Risk
		5.3.3	 Altering Muscle Architecture: The Roles of Contraction Mode and Muscle Excursion
		5.3.4	 Muscle-Tendon Junction Morphology
		5.3.5	 Aponeurosis Geometry
	5.4	 Conclusion
	References
6: Hamstring Injury Prevention and Implementation
	6.1	 Introduction
	6.2	 Hamstring Injury Prevention
		6.2.1	 General Warm-Up
			6.2.1.1	 FIFA 11 and FIFA 11+ Programmes
		6.2.2	 Eccentric Strength Training
			6.2.2.1	 Flywheel Training
			6.2.2.2	 Nordic, Russian or Hamstring Lowers
		6.2.3	 Stretching
		6.2.4	 Core Stability
		6.2.5	 Plyometric and Running Drill Interventions
		6.2.6	 Sports-Specific Interventions
	6.3	 Hamstring Injury Prevention Conclusion
	6.4	 Hamstring Injury Implementation
		6.4.1	 Practicalities of Implementation
			6.4.1.1	 How Can the Attitude Towards Hamstring Injury Prevention Be Positively Stimulated?
			6.4.1.2	 When Should Prevention Exercises Be Scheduled in Footballers?
			6.4.1.3	 Scheduling Prevention During a Competitive Season
			6.4.1.4	 Scheduling Prevention in a Weekly Schedule
			6.4.1.5	 Scheduling Prevention Before, During or After Training
			6.4.1.6	 Should Hamstring Injury Prevention Strategies Be Tailored to the Individual?
	6.5	 Hamstring Injury Implementation Conclusion
	References
7: Diagnosis and Prognosis of Hamstring Injury
	7.1	 Introduction
	7.2	 Diagnosis of Acute Hamstring Injury
		7.2.1	 Prognosis of Acute Hamstring Injury
			7.2.1.1	 Patient’s History
				Patient Demographics
				Previous Hamstring Injury
				Sport Participation
				Injury Mechanism
				Symptoms During or After Injury
				Self-Estimated or Physician-Estimated Time to Return to Play
			7.2.1.2	 Physical Examination
				Inspection
				Range of Motion
				Resistance Tests
				Slump Test
				Palpation
			7.2.1.3	 Can Return to Play Be Predicted at the Initial Assessment?
			7.2.1.4	 Follow-Up Clinical Examination Can Provide More Accurate Prognosis of Recovery Time
			7.2.1.5	 Evaluating Reinjury Risk
		7.2.2	 Imaging as Diagnostic and Prognostic Tool
			7.2.2.1	 X-Ray
			7.2.2.2	 Ultrasonography
		7.2.3	 Magnetic Resonance Imaging
			7.2.3.1	 MRI in Diagnosis and Informing Rehabilitation
			7.2.3.2	 MRI and Prognostication with Respect to Return to Play and Reinjury
				MRI-Negative Hamstring Injury
				Intramuscular Tendon Injury
			7.2.3.3	 Value of Imaging in Addition to the Clinical Examination
	7.3	 Diagnosis and Prognosis of Hamstring Injury Sequela
		7.3.1	 Differential Diagnosis of Posterior Thigh Pain
		7.3.2	 Evaluating (Risk) Factors that Affect Hamstring Complaints
		7.3.3	 Imaging in Hamstring Injury Sequela
		7.3.4	 Prognosis of Hamstring Injury Sequela
	7.4	 Diagnosis and Prognosis of Hamstring Tendinopathy
		7.4.1	 Clinical Diagnosis
			7.4.1.1	 Differential Diagnoses
		7.4.2	 Imaging in Diagnosis and Prognosis
	7.5	 Conclusion
	References
8: Muscle Injury Classification and Grading Systems
	8.1	 Introduction
	8.2	 History of Muscle Injury Classification and Grading
	8.3	 Modern Approaches to Muscle Injury Classification and Grading
		8.3.1	 MRI-Based Muscle Injury Scoring Scale for Return to Play—Cohen et al. [25]
		8.3.2	 MRI- and US-Based Acute Muscle Strain Classification System—Chan et al. [24]
		8.3.3	 The Munich Consensus Statement— Mueller-Wohlfahrt et al. [26]
		8.3.4	 British Athletics Muscle Injury Classification—Pollock et al. [27]
		8.3.5	 The MLG-R Muscle Injury Classification System— Valle et al. [28]
		8.3.6	 Grading Based on Connective Tissue Injury— Prakash et al. [34]
	8.4	 Conclusion
	References
9: Clinical Assessment of Hamstring Injury and Function
	9.1	 Introduction
	9.2	 Subjective Assessment
		9.2.1	 Open Questions for History Taking
		9.2.2	 Hamstring-Specific Questions
		9.2.3	 Patient-Reported Outcome Measures
			9.2.3.1	 Functional Assessment Scale for Acute Hamstring Injuries
			9.2.3.2	 Perth Hamstring Assessment Tool
			9.2.3.3	 Victorian Institute of Sport Assessment-Proximal Hamstring Tendons (VISA-H) Questionnaire
	9.3	 Physical Assessment
		9.3.1	 Inspection and Palpation
		9.3.2	 Hamstring Flexibility
			9.3.2.1	 Passive and Active Knee Extension Tests
			9.3.2.2	 Maximal Hip Flexion and Active Knee Extension
		9.3.3	 Hamstring Strength Assessment
			9.3.3.1	 Isometric Strength Measurement
				Lengthened State Hamstring Strength Measurement
			9.3.3.2	 Concentric and Eccentric Strength Measurement
			9.3.3.3	 Nordic Hamstring Strength Measurement
		9.3.4	 High-Speed Hamstring Flexibility and Apprehension Test (the H-Test)
		9.3.5	 Running and Sprinting Assessments
			9.3.5.1	 Running and Sprinting Loads
			9.3.5.2	 Speed and Force Production
	9.4	 Conclusion
	References
10: Rehabilitation of Hamstring Injuries
	10.1	 Introduction
	10.2	 General Principles
		10.2.1	 Rehabilitation Through Phases
		10.2.2	 Rehabilitation is Part of the Return to Sport Process
	10.3	 Rehabilitation of Acute Hamstring Muscle Injuries
		10.3.1	 Acute Management and Early Loading
		10.3.2	 Optimal Load Progression
		10.3.3	 Summary of Evidence
			10.3.3.1	 Early Time-Based Rehabilitation
			10.3.3.2	 Progressive Agility and Trunk Stability (PATS) Exercises
			10.3.3.3	 Hamstring Lengthening Exercises
			10.3.3.4	 Multifactorial Approach
			10.3.3.5	 Criteria-Based Rehabilitation and Running Progression
			10.3.3.6	 Passive Treatment Modalities and Static Stretching
			10.3.3.7	 Progression of Hamstring Strength Exercises During Rehabilitation
			10.3.3.8	 Monitoring ROM/Flexibility and Stretching Interventions During Rehabilitation
			10.3.3.9	 Running Progressions
			10.3.3.10 Lumbopelvic Control
			10.3.3.11 Summary
	10.4	 Rehabilitation After Proximal Hamstring Tendon Avulsions
		10.4.1	 Summary of Evidence
		10.4.2	 General Postoperative Recommendations and Rehabilitation Guidelines
	10.5	 The Young Athlete: Nonoperative Management of Avulsion Fracture Injuries
	10.6	 Rehabilitation of Proximal Hamstring Tendinopathy
		10.6.1	 Restoration and Recovery Phase
		10.6.2	 Sport-Specific Phase
	10.7	 Individualisation Throughout Hamstring Injury Rehabilitation
	10.8	 Conclusion
	References
11: Return to Sport After Hamstring Injuries
	11.1	 Introduction
	11.2	 Return to Sport Principles After Hamstring Injury
	11.3	 Return to Sport Decision
		11.3.1	 Multidisciplinary Review of Standards
	11.4	 Psychological Factors in Return to Sport
	11.5	 Sport-Specific Readiness
		11.5.1	 Workload
			11.5.1.1	 External Load Monitoring
			11.5.1.2	 Internal Load Monitoring
				Acute-to-Chronic Workload Ratio
	11.6	 Ongoing Monitoring and Prevention
		11.6.1	 In-Season Athlete Monitoring of Hamstring Function
	11.7	 Conclusion
	References
12: Optimising Hamstring Strength and Function for Performance After Hamstring Injury
	12.1	 Introduction
	12.2	 Deficits in Neuromuscular Function After Hamstring Strain Injury
		12.2.1	 Do Neuromuscular Deficits Contribute to Injury Recurrence?
		12.2.2	 Why Do These Deficits Persist?
	12.3	 Addressing Deficits in Sprint Performance
		12.3.1	 Avoiding Spikes in Sprinting Workloads
		12.3.2	 Ground Reaction Forces
		12.3.3	 Repeated Sprint Ability
		12.3.4	 Sprint Running Technique
		12.3.5	 Sport-Specific Running Requirements
	12.4	 Addressing Deficits in Strength and Muscle Architecture
		12.4.1	 Exercise Selection
			12.4.1.1	 Methodological Issues in Assessing Muscle Activation
			12.4.1.2	 Nordic Hamstring Exercise
			12.4.1.3	 Seated and Prone Leg Curl
			12.4.1.4	 Supine Sliding Leg Curls
			12.4.1.5	 Glute-Ham Raise
			12.4.1.6	 Razor Curl
			12.4.1.7	 Forty-Five Degree Hip Extension from Roman Chair
			12.4.1.8	 Stiff Leg Dead Lift and Romanian Dead Lift
			12.4.1.9	 Supine Bridges
			12.4.1.10	 Good Morning Exercise
			12.4.1.11	 Kettlebell Swing
			12.4.1.12	 Hip Thrusts
			12.4.1.13	 Squats, Leg Press and Lunges
		12.4.2	 Functional or Effective?
		12.4.3	 Exercise Selection for Hamstring Rehabilitation
		12.4.4	 Strength Deficits
		12.4.5	 Contraction Mode Emphasis
	12.5	 Conclusion
	References
13: When Hamstring Injury Rehabilitation Fails
	13.1	 Introduction
		13.1.1	 Epidemiology of Treatment Failure
		13.1.2	 Impact of Treatment Failure
		13.1.3	 Causes of Treatment Failure
	13.2	 Causes of Treatment Failure in Patients with Acute Hamstring Injuries
		13.2.1	 Incorrect Diagnosis
			13.2.1.1	 Tendon Avulsion Injury
			13.2.1.2	 Ischial Tuberosity Apophysis Avulsion Fracture
			13.2.1.3	 Adductor Magnus Muscle Injury
			13.2.1.4	 Gastrocnemius Muscle Injury
		13.2.2	 Inadequate Rehabilitation
			13.2.2.1	 Planning of Rehabilitation
			13.2.2.2	 Managing Risk Factors
	13.3	 Causes of Treatment Failure in Patients with Ongoing Posterior Thigh Pain, Including Hamstring Injury Sequelae
		13.3.1	 Incorrect Diagnosis
			13.3.1.1	 Hamstring Muscle-Tendon-Bone Complex-Related Causes
				Traction Apophysitis of the Ischial Tuberosity
				Myositis Ossificans
			13.3.1.2	 Non-Hamstring-Related Causes
				Neural Causes
				Vascular Causes
				Bone Pathology
				Joint Pathology
				Bursitis
		13.3.2	 Inadequate Rehabilitation and Restoration of Structure, Strength, and Function
			13.3.2.1	 Altered Structural Integrity
			13.3.2.2	 Muscle Architecture
			13.3.2.3	 Muscle Strength
			13.3.2.4	 Muscle Fatigue
			13.3.2.5	 Kinetic Chain Considerations
			13.3.2.6	 Hamstring Muscle Activation
	13.4	 Causes of Treatment Failure in Patients with Hamstring Tendinopathy
		13.4.1	 Incorrect Diagnosis
		13.4.2	 Inadequate Rehabilitation
	13.5	 Management of Treatment Failure in Patients with Acute Hamstring Injuries
		13.5.1	 Conservative Management
			13.5.1.1	 Anti-Inflammatory Medications
			13.5.1.2	 Injection Therapies
				Platelet-Rich Plasma (PRP)
				Actovegin®
				Traumeel®
				Stem Cells
		13.5.2	 Surgical Management
			13.5.2.1	 Tendon Avulsion Injury
			13.5.2.2	 Intramuscular Tendon Injury
			13.5.2.3	 Musculotendinous Injury
	13.6	 Management of Treatment Failure in Patients with Ongoing Posterior Thigh Pain, Including Hamstring Injury Sequelae
		13.6.1	 Conservative Management
		13.6.2	 Surgical Management
	13.7	 Management of Treatment Failure in Patients with Hamstring Tendinopathy
		13.7.1	 Conservative Management
			13.7.1.1	 Medical Treatment Modalities
			13.7.1.2	 Nonsteroidal Anti-Inflammatories (NSAIDs)
			13.7.1.3	 Extracorporeal Shock Wave Therapy (ESWT)
			13.7.1.4	 Injection Therapies
		13.7.2	 Surgical Management
	13.8	 Conclusion
	References