The flexibility and proper functioning of all myofascial chains are crucial for athletes, especially for long-distance runners. Due to the continuity of the myofascial structures, restrictions in one part of the body may cause excessive tension in others. The aim of our study was to evaluate the influence of short foot muscle exercises on muscle flexibility and the quality of movement patterns in amateur runners. Eighty long-distance runners, aged 20-45, were randomly divided into two groups: Group 1 (n = 48) and Group 2 (n = 32). Participants in Group 1 performed foot exercises daily for six weeks. Subjects in Group 2 were without any intervention. At baseline and after six weeks, the quality of movement patterns with the Functional Movement Screen and muscle flexibility was evaluated. In Group 1, significantly higher Functional Movement Screen values in individual tasks and in the total score were noted after six weeks. The total score increased from 17 to 18 points (Median (Me) ± half of interquartile range (IQR/2) (Standard Error of Measurement - SEM) 17 ± 1.5 (0.23) at baseline and 18 ± 1.5 (0.24) after six weeks) (p < 0.01), whereas in Group 2, its level remained at 16 points (Me ± IQR/2 (SEM) 16 ± 1.5 (0.31) at baseline and 16 ± 1.25 (0.31) after six weeks). In Group 1, the significant improvement in muscle flexibility was noted (e.g., results for external rotation muscles: (Mean ± SD (SEM) 60.3 ± 0.4 (1.50) at baseline and 62.4 ± 10.3 (1.49) after six weeks) (p = 0.005). In Group 2, significant improvement was observed only for one task in the Active straight leg raise test (p = 0.005 and 0.02). During the measurement of external rotation muscles, a significant decrease in flexibility was observed (Mean ± SD (SEM) 60.1 ± 9.0 (1.60) at baseline and 58.0 ± 8.5 (1.51) after six weeks) (p = 0.001). Plantar short foot muscle exercises may improve muscle flexibility in the upper parts of the body within myofascial chains and influence the quality of fundamental movement patterns. Such exercises may be beneficial for all physically active people and can be performed as part of overall fitness programmes. Moreover, including such exercises in daily training routines of long-distance runners, as well as by athletes in other sport disciplines is also recommended.
Keywords: Functional Movement Screen; energy transfer; muscle flexibility; myofascial chains; plantar foot muscles.