Article Text

How to optimise the fidelity of exercises in an unsupervised golf injury prevention programme? A pilot study
  1. Saskia Gladdines1,2,
  2. Denise Eygendaal2,
  3. Leonieke van Boekel3,
  4. Evert Verhagen4,
  5. Annechien Beumer1,5
  1. 1Department of Orthopaedic Surgery, Amphia Hospital, Breda, The Netherlands
  2. 2Department of Orthopaedics and Sports Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
  3. 3Department of Orthopaedic Surgery, FORCE (Foundation for Orthopaedic Research Care Education), Breda, The Netherlands
  4. 4Amsterdam Collaboration on Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam UMC, University Medical Centres – Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
  5. 5Coronel Institute of Occupational Health, Department of Public and Occupational Health, Amsterdam University Medical Centers, Amsterdam, The Netherlands
  1. Correspondence to Saskia Gladdines; saskia{at}


Background Golf is an individual sport that is usually done without the supervision of a trainer or coach. Therefore, an injury prevention programme in golf will primarily be performed without supervision and feedback. However, the effectiveness of any preventive exercise programme is determined by exercise fidelity.

Objective To investigate the different instruction options of an injury prevention programme on exercise fidelity in individual golfers.

Methods We randomly assigned golfers to one of three groups receiving different exercise instructions. One group received only instructional cards (A), one received only instructional videos (B) and a third group (C) received both instructional cards and videos. The golfers were allowed to familiarise themselves with the exercises based on the provided instruction option, after which we recorded their exercise execution on video. Two authors independently scored each exercise’s fidelity from these recordings.

Results In total, 18 golfers (12 women and 6 men, average age of 61.94 years) were equally divided across the 3 study groups completed 108 exercises. In group A 73.7% of exercises were executed as intended, in group B 88.6% and in group C 86.3%. Significantly more exercises were conducted correctly in groups B and C compared with group A (p<0.05).

Conclusion Golfers who received instructions that included a video explanation had a higher exercise fidelity when compared to only written instructions.

  • Golf
  • Exercises
  • Injuries
  • Prevention

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  • For optimal effectiveness, injury prevention exercises should be performed as intended. However, exercise fidelity is not often studied in evaluating intervention programmes.

  • If exercises are not performed as intended, an injury prevention programme may not work or will be counterproductive.

  • Exercise instructions are, in general, given by coaches or trainers who are qualified and trained to instruct and supervise the athletes during their warming-up and training. In individual sports, such as golf, qualified supervision is not present.


  • Our provided instruction allowed for a high rate of correctly performed preventive warm-up exercises in golfers.

  • Exercise fidelity was higher when instruction was provided in a video.

  • A video instruction should be added when disseminating the golf injury prevention programme.


  • When developing a preventive exercise programme that caters for an individual sport, the most optimal instruction method should be investigated as part of the intervention development process to increase exercise fidelity.

  • Assessing exercise fidelity during the development stage will change the implementation and dissemination of a programme.


Like any other sport, golf carries the risk of injury.1 2 Specific warm-up programmes have been shown to lower the risk of injury in various sports.3 Warm-up programmes and risk management approaches have been described in relation to golf performance and injury risk reduction.4 5 However, their effectiveness in reducing injury rates remains to be evaluated. Using the knowledge transfer schema (KTS), we created the Golf Related Injury Prevention Programme (GRIPP) intervention for recreational golfers.6 The full protocol for developing this intervention was previously published.7

The success of any programme designed to prevent sports injuries depends on how well it is disseminated and implemented.8 9 Exercise fidelity is crucial to creating an optimal implementation outcome for an injury prevention programme. Exercise fidelity measures whether an athlete can perform the exercises with the correct technique and according to the instructions given.9 Incorrect performance can under or overestimate the effectiveness of an intervention. To measure exercise fidelity, sporters needed to be instructed.

The way exercise instructions are given influences the performance and learning curve.10 In trainer or coach-based sports, the instructors are mostly previously taught during an education meeting and supported with instruction manuals and videos.9 11–15 They provide the exercises to their sporters with visual demonstrations and oral instruction.16 An advantage can be that trainers give feedback and can differentiate between techniques such as internal or external focused instructions to improve performance.10 While golf is an individual sport, mostly played without supervision, specific instructions and directions should target participants directly.17 18 The performance of injury prevention programme by athletes in individual sports is challenging because of limited options for feedback and support. There is restricted interaction with trainers, less or no team support, primarily individual practice and social influence of team members.19 In this pilot study, we compared various strategies to instruct individual golfers to perform golf-specific warm-up exercises correctly.


Study design

This pilot study was a randomised pilot trial to investigate if golfers can correctly perform the unsupervised exercises of the GRIPP programme after being provided with different instruction forms. Participants were randomly assigned to one of three instruction methods: (A) only an instruction card, (B) an instructional video and (C) an instruction card and video. We published a detailed description of the development and content of the GRIPP exercise programme previously.7


Active golf players were asked to partake in this pilot study. We approached potential participants at random at a single golf club. When a player was interested in participating, we gave them our study’s details verbally and in writing. All players who agreed to participate in the study provided written informed consent. We included players with a World Handicap System (WHS) handicap of 36 or lower; ≥45 years of age; a playing frequency of at least nine holes a week; willing to perform the GRIPP intervention and understanding of the Dutch language.

Sample size

In the absence of previous studies that describe the value of instruction methods for exercise fidelity in injury prevention programmes, we could not calculate an a priori power calculation. Hence, we included at least six players in each study group based on pragmatic considerations.


We randomly assigned players by drawing a ticket number from a bowl to one of three groups (A, B and C). After the group assignment, we provided each group with different exercise instructions. The instructions for group A consisted only of instructional cards, group B only received instructional videos and we presented group C with both the cards and videos.


The exercises of the GRIPP programme were developed using the KTS. The exercises are provided in table 1. We refer to the previously published study protocol for further details on the exercises and programme development.7 Based on their randomised group, the players received an instruction card on paper and/or an iPad to watch the instruction video. A similar voice text was used in the instruction video as on the instruction card, with small additional instructions in the video (table 1). No corrections were given during the practice and performance time by the researcher (SG). The players individually practised each exercise using their assigned instructional method until they declared to be familiar with the exercise. The player then performed the exercise, which SG recorded on video. This procedure was repeated until all six exercises were recorded. All exercises were performed and recorded once on the same day. During the assessments, we minimised interaction between the researcher and the players. There was no interaction possible between participants while all exercises were practised individually.

Table 1

The GRIPP intervention for golfers7

Outcome measures

A survey collected general demographic information such as gender, age, handicap and the number of holes per week. We developed an assessment tool based on the process of Fortington et al9 and adapted this to our exercises. The assessment tool is provided in online supplemental file A. We used the instructions on the instructional card as a foundation for the assessment tool’s criteria. This provided us with fidelity criteria for each exercise, ranging from 4 to 10 criteria depending on the exercise. Based on the performance video recordings of each participant each criterion was scored from the exercise independently by two assessors (SG and JvTS), as performed correctly (yes) or performed incorrectly (no).

Supplemental material


Due to the instruction methods’ nature, we could not blind the players for their group allocation. The primary assessor (SG) was also not blinded because she distributed the exercise instruction to the participants. However, the second assessor (JvTS) was blinded for group allocation. In case of a difference in scoring, the two assessors conferred and reviewed the exercise a second time. After that, the second assessor decided if there was still disagreement.

Data analysis

We performed the analyses in IBM SPSS Statistics for Mac (V.28) and Microsoft Excel for Mac (V.16.73). We compared groups’ baseline characteristics with a χ2 independence test and a one-way analysis of variance. We assessed the inter-rater agreement between the two assessors with a Cohen’s kappa to provide insight into the reliability of the assessment tool.20 Descriptive statistics were used to describe the study population and exercise fidelity. We calculated exercise fidelity as the percentage of correctly performed criteria for each of the six exercises by dividing the total number of exercise criteria performed correctly by the total number of criteria. A χ2 independence test was used to compare groups. If a significant difference (p≤0.05) was found, a χ2 pairwise Z-test was performed to identify which groups differed.


Participants and recruitment

In this randomised pilot study, eigtheen golfers (12 females and 6 males) were included during three enrolment days in April 2021. During the enrolment day, the assigned intervention was immediately performed, and all participants completed the intervention of their specific group. The baseline characteristics were similar between the groups. The average age of the included golfers was 61.94 years (SD 11.41), the average WHS handicap was 17.12 (SD 6.13) and the average number of holes played per week was 36.79. (SD 12.35). Gender distribution was equal across all groups. Thirteen of eighteen golfers did some form of exercise before playing (table 2).

Table 2

Baseline characteristics

Inter-rater agreement

In total, 864 criteria were scored between both assessors and immediate agreement was reached for 832 of these (96.2%). This resulted in an inter-rater agreement of 0.88 (Cohen’s kappa), which indicated almost perfect agreement.

Fidelity assessment

Exercise 4 had the highest exercise fidelity for all three groups, exercise 6 had the lowest for groups A and C and exercise 3 had the lowest for group B (table 3).

Table 3

Total percentage of correct performed items per study group

Between-group differences

Overall, we found a significant difference (p<0.001) between the groups, and there was a difference between group A (instructional card) and group B (instructional video), and group A (instructional card) and group C (instructional card and video) (p<0.05). Differences between the study groups differed between the individual exercises, with no group differences for exercises 2, 3 and 4 (table 3).


In this study, we found that golfers who received explanatory video instruction with or without printed card instructions performed better on exercise fidelity than those who received only an instruction card.

Individually performed unsupervised exercises reflect daily golf practice.17 Little is known about the correct performance of exercises in unsupervised sports settings. Unsupervised exercise programmes have previously been studied in randomised controlled trials for tennis and athletics.17 18 21 Following an ankle sprain, unsupervised exercise instructions were compared with exercising with an app or printed booklet instructions in preventing recurrent ankle sprains in athletes.22 The instruction methods produced comparable in terms of compliance and recurrence rates results.22 In treating knee osteoarthritis, a self-directed online guided programme with supported text messages improved knee pain and function.23

In a physical therapy setting, illustrated instructions of exercises were compared with video instructions. The performance of exercises with video instructions outperformed illustrated instructions regarding performance quality.24 This is consistent with the findings of our study. Unsupervised video instruction increases the percentage of exercises performed correctly compared with only card instruction. Our study found a significant difference in exercises with more complex movements, such as rotations and diadochokinetic. This could be due to the video instruction as visual cues while learning a new task enhances motor learning.16 24–26 Observing a model decreases the trial-and-error process and enhances increased performance.27 28 However, there is little evidence on how a visual cue or written task will affect motor learning and how a task needs to be presented.27 29 We previously tested the instruction readability and understandability of the exercise instructions during development.

Measuring the correct performance of exercises is rarely studied in team sports studies. It is assumed that coaches/trainers in team sports give adequate instructions to perform the exercises correctly.9 11–13 Fortington et al9 developed an assessment tool to monitor the correct performance of exercises to address this. Their observational checklist showed a high inter-rater reliability score. The scoring system of Fortington et al9 was scored with two assessors during a training session, while we used video records to score. The assessors in our study might be able to score more precisely because they could repeat the recordings. However, the scoring system of correct performance of exercises is similar in individual sports and is, therefore, transferable to our study.


We need to be aware of the Hawthorne effect.30 Our participants knew that the goal of our study was on exercise execution and their exercises were being recorded. They may have performed the exercises more conscientiously than they would have done in a ‘normal’ warm-up situation. This may have shown us an overestimation of the correct performed exercises. In contrast, the participants might be nervous and experience tension because of being watched. Hence, we did limit our interaction with the participants to account for any effects the above might have had.

Practical application

If a sports injury prevention programme is not implemented properly, its effectiveness may be underestimated or limited. It is not sufficient to simply complete exercises and monitor them during a trial. Exercise fidelity, or the correct performance of exercises, must also be evaluated. Correct performance is rarely studied in intervention programmes. Our programme differs from previous studies in that we provide unsupervised exercises. Future studies need to be aware that assessing the exercise fidelity of a programme is the final stage before investigating the intervention effectiveness of an unsupervised programme. The development of a programme consists of several stages. A development tool such as the KTS can be assistive for real-life practicality.6 During the development stages, in which end-users are involved, attention is necessary for how sporters want to be instructed. If the instructions and the goal are clear, it will likely improve the correct performance of exercises and future programme implementation.


The effectiveness any preventive exercise programme is determined by the programme’s exercise fidelity. Golfers who received an instructional video or an instructional video in combination with an instructional card had a significantly improved performance of the exercises compared with only an instructional card.

Ethics statements

Patient consent for publication

Ethics approval

The Medical Review Ethics Committee Amsterdam Medical Centre approved the study. It was not subject to the Medical Research Involving Human Subjects Act (WMO, the reference number is W21-046#21.140). Written informed consent was obtained from all subjects. Participants gave informed consent to participate in the study before taking part.


We thank Julia van Tuyll van Serooskerke for helping with the checklist and reviewing the exercises. Also, we greatly thank all the golfers for participating in this study.


Supplementary materials

  • Supplementary Data

    This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.


  • Twitter @SaskiaGladdines, @evertverhagen

  • Contributors AB conceived the study. AB, DE and SG contributed to the conceptualisation of the study. SG collected the data. SG, LvB and EV contributed to data analysis and interpretation. The first draft was written by SG. All authors critically revised and contributed to the manuscript. All authors approved the final version of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests EV is the editor in chief of BMJ Open Sports and Exercise Medicine.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.