# Noise Source Identification in Training Facilities and Gyms
## 6 Discussion and Guidelines for Noise Reduction  
The presented case is a good representation of an average CrossFit box. The identified and classified noise sources are representative of other similar facilities. It is clear that acoustic levels will differ between enclosures, but the dominant noise sources will remain similar. The conducted measurements indicate potential health hazards can be caused by the investigated exercises. High LApeak values paired with poor room acoustics can potentially have a harmful influence on the wellbeing of trainees as well as reducing the life comfort of other residents, and most certainly can initiate noise-related complaints of others or nearby building users. Additional long-term acoustic measurements are needed to fully identify the potential hazards and define their influence on health, comfort, and wellbeing. Acoustic measurements should be carried out over longer exposure times, for example, during an average business day of a training venue.  
Noise problems are most effectively solved at the source. All barbell movement patterns investigated above caused excessive noise levels, which could be reduced significantly or even disregarded if the trainee fully controlled each stage of the movement pattern. Dropping of the barbell from locked positions should not take place in the case of light weights, such as ones used during group exercises. The lack of barbell control on the eccentric part of the movement pattern not only compromises the training effects, but also causes the barbells to be dropped onto the ground or training equipment, such as stands or jerk boxes, to cause noise, which should not be emitted in the first place. An additional benefit of proper exercise form is reduced stress on the weightlifting equipment. Proper education on this matter, with an emphasis on the personal benefits of the trainee due to  
Figure 9: Classification of possible noise sources.  
proper movement form, should be promoted in all facilities equipped with barrels and weights. Plyometric box jump exercises tend to be noisy as well, but in this case, the landing of the trainee on the box is a major part of the exercise and only modification of the plyobox structure and materials can help with noise reduction at the source.  
The implementation of acoustic materials with a high absorption coefficient is proven to reduce the reverberation time significantly. This solution is especially suited in the case of large open areas, such as the one presented in Figure 2, where the positioning and possible areas of application of the acoustic material are not limited as in the case of residential buildings and offices.  
Vibration isolation is a way to reduce the transmission of excitation signals onto other potential noise-emitting surfaces. Vibration isolation, used in mechanical engineering to reduce vibrations transmitted from the vibration source to other machine elements, devices, or buildings, has been studied by numerous researchers [29; 30]. Passive vibration isolation systems in the form of foam or soft rubber [31; 32] are used as well as semi-active [33; 34; 35; 36] or active ones [33; 37; 38]. The application of passive vibration isolation as presented in this paper seems to be the best solution for heavy weight-induced impact, due to both economical and practical reasons. Weightlifting platforms equipped with damping materials resistant to mechanical wear, when effective, in many cases are expensive and suited to accommodating one liter during training, so application for group exercise is especially costly. Areas predestinated for group workouts especially prone to strong and periodic impacts should incorporate additional passive vibration isolation in the form of damping mats.