Keywords

1 Introduction

Powerlifting is a discipline that belongs to the strength sports group. It consists of three exercises: a squat with a barbell on one’s back, a bench pressing in a supine position, and deadlifting [1]. Significantly, exercises specific to this sport are performed not only by powerlifters but also by bodybuilders, strongmen, CrossFit practitioners, and during rehabilitation [2] (e.g., deadlifting is used to stabilize the spine in cases of discopathy [3]). These movements are also treated as a complement during preparatory training for all kinds of sports (such as snowboarding, skiing, or cycling) [4]. Due to the large number of applications of these exercises and their sophistication, they are associated with a significant number of injuries. For triathletes alone, the statistics are 1.0–4.4 injuries per 1000 h of training [5]. For CrossFit practitioners, the injury statistics are 0.2 to 18.9 injuries per 1000 h of training, with as many as 8.7% requiring surgery [6]. The reasons for this phenomenon are found in too much load, too little rest time between sets, and incorrect technique of performing these exercises. The last reason is important because it can be reduced by improving exercisers’ technique and movement patterns. This paper proposes a solution based on learning movement patterns using a virtual reality application.

VR applications supporting training and rehabilitation are increasingly common in the daily functioning of athletes [7], physiotherapists [8], and ordinary non-specialists. They allow both to conduct enjoyable workouts in a diverse environment (which is extremely useful, for example, in the physiotherapy of children [9]) and provide immediate feedback and the ability to monitor their progress [10,11,12]. In addition, for professional athletes, are used to analyze and optimize the movement patterns used [13,14,15,16]. Furthermore, the argument for the research is the variety of sports and exercises and other health and movement fields (such as applications for training surgeons) for which applications using virtual reality have already been created to teach [7, 17]. The literature data mentions the use of VR technology to assist strength athletes, however, mainly in the motivational sphere. Unknown to the authors are solutions for learning the movement patterns of powerlifting using VR applications [18].

2 VR Application Development

The application’s main purpose is to allow one to safely learn the exercises included in the powerlifting or correct previously acquired, incorrect movement patterns – performing exercises without load will not cause injury. The critical element in these exercises is the correct handling of the barbell, which was taken into account when creating the application. In a significant number of cases, according to specialists, this is a sufficient condition to reduce the frequency of injuries resulting from incorrect exercise significantly. This statement is supported by the fact that the guidance of the barbell forces the body position of the exerciser. After consulting with a powerlifting coach, this was accepted as a sufficient condition for the VR application.

2.1 VR Application - Selecting the Type of Training

A VR game was created that met the outlined objectives. The player can choose a specific exercise. In the first stage, a video showing the correct performance of the exercise is displayed.

Then the player can choose one of four levels of difficulty. Levels of difficulty differ in the number of visible elements that determine the correct trajectory of the barbell and additionally allow the player to monitor his progress.

2.2 VR Application - Proper Training

Before performing an exercise, the player is informed of the correct starting point. For standing exercises (deadlift and squat), it is the virtual barbell’s position (Fig. 1).

Fig. 1.
figure 1

Squat training station with a barbell, with visible starting points

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The user’s position on the bench is additionally controlled by the horizontal bench press. During the execution of the exercise, the path of the barbell movement is examined, and the transition along the correct trajectory is checked, as well as the maintenance of the horizontal position of the barbell (required for each trained exercise). In addition, as the user performs repetitions, advice from a “virtual coach” appears, including critical elements of each exercise. The user performs five repetitions of an exercise. A special counter helps him control the number of repetitions. After completing the appropriate number of repetitions, the player proceeds to check the results.

2.3 VR Application - Results and Progress Monitoring

The results are then assigned to a 5-grade scale and presented to the player in an iconic, currently popular, and easy-to-understand manner. The results are displayed in three tables. The first gives the user feedback on each of the repetitions for a given exercise, with easy-to-understand graphs. The number two board describes how to improve exercise performance. The last board graphically depicts the overall averaged training score in a humorous way.

2.4 VR Application - Environment

The entire training room is located in a mountainous environment (Fig. 2) which is meant to make the learning process even more enjoyable. In addition, the app includes motivating voice comments and elements to increase mental immersion. All these elements aim to extend training time by making it more attractive.

Fig. 2.
figure 2

Environment of application

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3 Conclusion and Further Steps

A game was created that allows players to improve their technique in powerlifting exercises. At the time of writing, the prototype application has been tested by a strength triathlete coach. The testing results are auspicious, and necessary corrections have been made, so the application is ready for further research on a larger group of people. In addition, the use of VR games for learning or simulating sports [19, 20] and rehabilitation [8] allows us to assume that the application has a significant case to meet its goal, which is to reduce the number of injuries during training. The prototype application has also received positive feedback from physiotherapists.

The next step of the work will be to conduct tests on a larger number of users with different proficiency levels. The tests will be conducted under the supervision of a powerlifting coach. The test subjects will be divided into two groups. Each participant will get to watch a demonstration video at the beginning. Subjects in group one will then perform each of the exercises (at an adequate, safe load for the user’s strength) with no prior in-game training. Participants in group two will do the in-game training first and then the gym training second. At the very end, the progress will be evaluated by the trainer. Thus, the real impact of performed exercises in virtual reality on the correctness of authentic movement patterns will be analyzed. The impact of the simplifications adopted, including analysis of the barbell movement alone without reference to characteristic body parts, on the correctness of the training performed will also be examined. The results of the study will be described in subsequent articles.