Single-Case Research Methods

Introduction to Single-Case Research

• Single-case research designs are a research method used in sport and exercise science to increase knowledge.
• This type of research can complement the existing literature that relies on traditional group designs.
• The principles apply across various domains including coaching, biomechanics, physiology, and nutrition.

What is Single-Case Research?

• Single-case research involves collecting data from typically one participant to explore changes in response to manipulated variables.
• Variations exist, like investigating outcomes at a group level where the "single case" is an identifiable group.
• Multiple-baseline designs report data from several participants separately, strengthening conclusions through replication of effects.
• The reliance on single individual data makes it problematic for some.
• This book aims to shows how single-case research designs can effectively contribute to sport and exercise literature.

Case Studies vs. Single-Case Research

• Case studies involve observations under uncontrolled conditions, differing from single-case research.
• Case studies can be used to illustrate understanding and development in sport and exercise.
• Case studies have stimulated current understanding of human behaviour and functioning
• Vealey and Walter (1994) used Darrell Pace as case study, however, it is impossible to know what helped him to success.
• Mace, Eastman, and Carrol (1987) study reveals the essence of a case study, but also reveals the limitations.
• Case studies lack the control and rigor needed to draw definite conclusions from the data.

Single-Case Research Designs

• Unlike case studies, single-case research designs offer experimental control and exclude threats to validity.
• Ebbinghaus's memory studies demonstrated the possibility of rigorous research with a single participant.
• A researcher can control variables, introduce interventions, and examine their influence.
• Repeatedly measuring a target variable and establishing a baseline is vital.
• The participant serves as their own control, comparing changes after intervention to the baseline phase.

A-B Design

• A common design is the A-B design, comparing a baseline phase (A) with an intervention phase (B).
• Barker and Jones (2008) use hypnosis to enhance mood and self-efficacy in soccer players is an example of A-B design.
• A potential problem is that any observed differences may be due to maturation, not the intervention.

Intervention Withdrawal Designs

• Intervention can be withdrawn in designs such as A-B-A, or withdrawn and then reintroduced such as A-B-A-B.
• If the variable of interest changes in line with the introduction or withdrawal of the intervention then confidence will raise.
• Not all interventions can be withdrawn (e.g., cognitive restructuring).

Multiple Baseline Designs

• Multiple-baseline designs can also be used.
• The coach hypothesizes feedback reduce the tendency for the player to 'coast' during games and increase game involvement.
• Game involvement may be assessed by a pre-determined set of criteria (e.g., number of passes, tackles, line breaks).

Demonstrating Replicability

• By using A-B-A-B designs, it is possible to demonstrate the replicability of effects (Kratochwill et al., 1984).
• Observing similar changes across participants in a multiple-baseline design supports the technique's efficacy.
• Heyman (1987) study with an amateur boxer. He ceased using a hypnotic intervention that help silencing the sound of the crow.

Why Single-Case Research Designs Are Useful

• Single-case research designs should not replace group designs.
• Single-case research designs and group designs can be complementary
• Used to produce target changes in athletes' or exercisers' thoughts, emotions, behaviour, physical states, techniques or performances.

Advantages of Single-Case Research

• The efficacy of the interventions used is demonstrated at an individual level
• Single-case research promotes naturalistic applied settings
• Naturalistic settings also encourage treatment effects to be observed on ecologically valid tasks
• Single-case research can take place in naturalistic settings and be ecologically valid.
• Single-case research is the evaluation of practice that involves investigating the outcome of an intervention as it would actually be delivered

Limitations of Standard Methods

• Treatment effect may depend on idiosyncratic client features
• Group study findings may mask individual differences in responding to interventions.
• Practitioners is seldom concerned with bringing about a statistically significant change in group averages
• Group designs produce 'conditional' knowledge

Unique Populations

• Single-case research provides the opportunity to explore the efficacy of techniques in unique or uncommon populations.
• Group designs are intended to produce 'conditional' knowledge

Importance for Researchers and Practitioners

• Used with small samples or individuals
• Methods to rigorously determine change along with consultant and/or coach effectiveness are important issues for the sport and exercise community stakeholders.
• Demonstrating effectiveness is of equal importance to both researchers and practitioners.

Overlooked Approach

• Single-case research remains somewhat underused in sport and exercise.
• Practitioners in sport and exercise area do not understand how best to apply single-case method
• This can be perhaps be exacerbated by an irregular coverage of single-case research methods.
• Single-case research represents an effective (yet currently underused) complement to group research allowing researchers and consultants to determine the efficacy of biomechanical.