Football is inherently a demanding sport. The fact that it is played on large fields, on different surfaces, and under various weather conditions requires individuals involved in the game to demonstrate high-level physical performance (Liu et al., 2025). One essential component of football is the referee, who plays a crucial role in managing the match and ensuring fair play. Football referees are required to sustain a high level of physical exertion comparable to that of players, regardless of environmental conditions (Liu et al., 2025; Baydemir et al., 2021). Unlike players, whose movements are influenced by ball location and playing position, referees must move across almost the entire field to maintain an optimal viewing angle and minimize decision-making errors.

During a 90-min match, referees typically cover approximately 10–12 km and perform repeated high-intensity actions such as accelerations, decelerations, directional changes, and backward running (Castagna et al., 2007; Weston et al., 2007). These continuous demands impose substantial mechanical load on the musculoskeletal system, and limitations in mobility, stability, or movement control may increase the likelihood of injury (Mallo et al., 2009). Therefore, improving movement quality and functional efficiency is highly relevant for referee performance and physical preparedness during match officiating. Movement quality reflects the efficiency and coordination with which fundamental movement patterns are executed and is closely linked to key motor abilities such as speed, agility, balance, and power. Previous research in team-sport athletes has demonstrated meaningful associations between functional movement quality and physical performance characteristics, indicating that higher-quality movement patterns may support more effective and economical execution of sport-specific tasks. These relationships have been demonstrated in various athletic populations, where FMS performance has been associated with speed, agility, jump performance, and selected anthropometric characteristics (Koźlenia et al., 2020; Alexe et al., 2024; Nicolozakes et al., 2018). Furthermore, functional movement quality has been linked to broader physical and health-related markers, suggesting that FMS performance may reflect multidimensional aspects of physical preparedness (Farrell et al., 2021; Cornell et al., 2017). In this context, assessing movement quality provides insight not only into potential injury risk factors but also into the functional foundation underpinning athletic performance.

Functional movement assessments are used to identify deficiencies and asymmetries in fundamental movement mechanics and to evaluate overall movement quality (Cook et al., 2014). In this context, the Functional Movement Screen (FMS) is a widely used tool for examining movement quality, highlighting limitations in mobility and stability, and identifying potential deficits in motor control (Cook et al., 2014). Previous research has shown that lower FMS scores may be associated with an increased risk of injury in athletic populations (Kiesel et al., 2007; Bonazza et al., 2017). Although this relationship has been examined primarily in players, evidence focusing on functional movement quality and FMS performance in football referees remains limited. Considering the high physical demands placed on referees during matches, assessing their movement quality and implementing targeted training programs may be particularly important (O'Connor et al., 2011).

Mobility and stability constitute the core components of functional movement ability. Mobility refers to muscle flexibility and joint range of motion, whereas stability involves postural control and balance. Adequate mobility may enhance movement efficiency during dynamic actions such as rapid direction changes, accelerations, and abrupt stops, while insufficient mobility or stability may increase the risk of injury (Hrysomallis, 2013). These components are fundamental targets of functional training interventions aimed at improving movement quality and neuromuscular control. Traditional mobility exercises are commonly performed on stable or rigid surfaces. However, training on soft or compliant surfaces may provide additional proprioceptive challenges and contribute to improvements in postural stability and neuromuscular control (Paillard, 2012). Such training environments may stimulate sensorimotor adaptations that support movement coordination and functional performance, potentially leading to improvements in functional movement patterns and FMS outcomes (Winter et al., 2022). Given the documented associations between functional movement quality and motor performance parameters in team-sport athletes, interventions targeting mobility and stability under increased neuromuscular demand may have practical relevance beyond isolated movement screening scores (Koźlenia et al., 2020; Alexe et al., 2024).

Despite these potential benefits, the effects of structured mobility exercises performed on soft surfaces on FMS scores have not been sufficiently investigated, particularly in football referees. Moreover, it remains unclear to what extent mobility training performed under unstable or compliant conditions can enhance movement quality as reflected by standardized functional assessments rather than isolated performance metrics. Given the high match demands experienced by referees, examining the impact of soft-surface mobility training on movement quality may provide a scientific basis for designing more effective conditioning strategies that support functional efficiency and neuromuscular preparedness. Based on the theoretical framework linking mobility, stability, and neuromuscular control to functional movement quality, it was hypothesized that:

A 12-week unstable/compliant surface–based mobility exercise program would result in significantly greater improvements in total FMS score in the experimental group compared with the control group; and

Participant characteristics at baseline are presented in Table 1. The experimental and control groups showed comparable demographic and anthropometric profiles. Pre- and post-intervention FMS component scores and total FMS scores are summarized in Table 2. The control group demonstrated minimal changes from pre-test to post-test across all FMS outcomes, whereas the experimental group showed noticeable improvements in several FMS components and in total FMS score. The 2 (group: experimental vs. control) × 2 (time: pre-test vs. post-test) mixed ANOVA revealed statistically significant group × time interaction effects for Total FMS score (p < 0.001) as well as for Deep Squat (p = 0.004, partial η² = 0.14), Hurdle Step (p < 0.001, partial η² = 0.49), Active Straight Leg Raise (p = 0.043, partial η² = 0.07), Trunk Stability Push-up (p = 0.001, partial η² = 0.17), and Rotary Stability (p < 0.001, partial η² = 0.42) (Table 3). These interaction effects indicate that the experimental group demonstrated significantly greater improvements over time compared with the control group, with effect sizes ranging from moderate to large depending on the FMS component. The group × time interaction for total FMS score is illustrated in Figure 1. In contrast, the group × time interaction effect was not statistically significant for In-line Lunge (p = 0.206, partial η² = 0.03) and Shoulder Mobility (p = 0.689, partial η² < 0.01) (Table 3), indicating comparable pre-to post-test changes between groups for these movement patterns.

Figure 1 illustrates the group × time interaction for total FMS score, showing a marked increase in the experimental group from pre-to post-test, while the control group remained relatively stable.

The present study investigated the effects of a 12-week unstable/compliant surface–based mobility exercise program on Functional Movement Screen (FMS) performance in male football referees. The main finding of this study was that the experimental group demonstrated significantly greater improvements than the control group in total FMS score, suggesting that this type of mobility training is associated with improvements in movement quality indicators measured by the FMS.

In addition to improvements in total FMS score, the mixed ANOVA results indicated significant group × time interaction effects for key movement components including Deep Squat, Hurdle Step, Active Straight Leg Raise, Trunk Stability Push-up, and Rotary Stability. These outcomes reflect improvements in lower-extremity mobility, dynamic balance, core stability, and rotational control, which are essential physical qualities for football referees due to the frequent accelerations, decelerations, directional changes, and multi-planar movements required during match officiating. Referees perform under repeated high-intensity demands, and efficient movement patterns may support more economical movement execution during match activities.

From a physiological and neuromuscular perspective, the observed improvements may be explained by the specific demands imposed by training on unstable and compliant surfaces. Exercises performed under unstable conditions increase postural challenge and modify afferent sensory input from mechanoreceptors located in muscles, tendons, and joint structures. This enhanced sensory feedback promotes greater sensorimotor integration within the central nervous system, facilitating improved coordination between agonist, antagonist, and stabilizing muscle groups (Paillard, 2012; Zech et al., 2010; Winter et al., 2022).

Furthermore, soft-surface training has been shown to increase activation of deep stabilizing musculature and to enhance trunk control through both feedforward and feedback motor control mechanisms. Improved feedforward activation may allow referees to better anticipate perturbations during rapid changes of direction, whereas enhanced feedback control contributes to effective postural corrections during unexpected balance challenges. These neuromuscular adaptations may explain the substantial improvements observed in trunk stability and rotary stability FMS components, which are particularly sensitive to deficits in core control and intermuscular coordination.

Improvements in lower-extremity mobility-related components such as the Deep Squat and Active Straight Leg Raise may also be attributed to enhanced joint range of motion and reduced neuromuscular inhibition following repeated exposure to controlled instability. Training on compliant surfaces may promote more efficient regulation of joint stiffness and improved intermuscular coordination, allowing referees to execute complex movement patterns with greater symmetry and control.

The findings of this study are in line with previous literature suggesting that balance- and mobility-oriented training programs can positively influence functional movement performance (Zech et al., 2010; Paillard, 2012; Winter et al., 2022). The FMS has been widely used to assess movement quality and identify potential limitations in fundamental movement patterns. Given that football referees operate in environments requiring high levels of multi-joint coordination, improving movement quality through targeted mobility and stability training may provide practical benefits for performance preparation. Therefore, incorporating soft-surface mobility exercises into referee conditioning routines may be considered a feasible and sport-specific approach to support functional movement capacity in this population.

In conclusion, a 12-week unstable/compliant surface–based mobility exercise program performed twice weekly significantly improved total FMS score and several key movement components compared with the control condition.

These findings suggest that this form of mobility training is associated with improvements in functional movement quality, dynamic balance, and neuromuscular control in football referees.

Incorporating such training into referee conditioning programs may support movement efficiency and physical preparedness for match demands; however, direct effects on performance or injury outcomes were not assessed in the present study.

This study has several limitations. First, the sample consisted of male amateur football referees, which may limit the generalizability of the findings to female referees or elite-level officials. Second, although FMS scoring was conducted independently by two trained raters and the mean score was used for analysis, formal inter-rater reliability statistics (e.g., intraclass correlation coefficients) were not calculated. While rater training and standardized scoring procedures help reduce measurement error, the absence of empirical reliability estimates limits confidence in the objectivity and reproducibility of the FMS scores. Furthermore, because individual rater-level data were not archived, inter-rater agreement statistics could not be computed post hoc, and future studies should retain individual scoring sheets to allow formal ICC calculation. Third, FMS component scores are ordinal measures; although they were treated as quasi-continuous variables in accordance with common practice in the FMS literature, future studies may benefit from complementary biomechanical or kinematic assessments to strengthen interpretation of movement-quality changes. Finally, the absence of long-term follow-up precludes conclusions regarding the retention of observed improvements over time.

These findings suggest that incorporating soft-surface mobility exercises into referee conditioning programs may enhance movement quality and functional stability, with potential implications for movement efficiency during match officiating. Future studies should examine long-term retention of these adaptations, include female and professional referees, and compare different training surfaces and intensity progressions to optimize functional movement outcomes. Additionally, future research incorporating direct performance metrics and injury surveillance would help clarify the practical significance of improvements in functional movement quality.