**3. Results**

### *3.1. Journals and Years*

The papers included in the systematic review were published in several scientific journals. The journals could be divided into three fields of research: Engineering and Technology (78.0%), Sport Science and Medicine (14.0%) and Biomechanics (8.0%) (Figure 2a). The number of papers published each year since 2004 is shown in Figure 2b.

**Figure 2.** (**a**) journal distribution; (**b**) publication frequency by year. The total number of papers since 2004 is 35.
