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Soccer referees are at risk of injury due to the physical demands of their role. This study evaluated the impact of the 24-week FIFA 11+ Referees training program on the quality of change of direction (COD) maneuvers in elite soccer referees. Eighty-one male referees were randomly assigned to either the 11+ referee group (n = 40) or a control group (n = 41). The intervention group replaced their usual warm-up routines with the FIFA 11+ program, while the control group continued their standard training. Both groups were assessed using the cutting movement assessment score (CMAS) before and after the intervention. The results demonstrated significant improvements in CMAS scores for the 11+ referee group at all tested angles (45°, 70°, and 90°), with the most notable improvements observed at 90° angles. These findings indicate that the FIFA 11+ Referees program enhances COD maneuver quality, which is critical for injury prevention. Implementing this program may therefore improve movement quality and reduce injury risks among soccer referees. Further research should explore the program’s long-term efficacy and applicability across different populations and injury factors.

Background: Strength and conditioning experts widely recognize the dynamic strength index (DSI) as a tool for assessing an athlete’s ability to utilize strength in dynamic actions. The DSI is calculated as the ratio of peak force in dynamic actions versus isometric ones. To date, the influence of fatigue on the DSI is still not fully understood. This study aimed to explore the effects of both dynamic and isometric fatigue tasks on the DSI. Methods: A total of 24 physically active participants underwent fatigue tests involving repeated countermovement jumps (dynamic) and repeated isometric mid-thigh pulls (isometric) in separate visits. Results: The results revealed a marked drop in performance, with dynamic force showing a more significant reduction (p < 0.001; d = 1.57) than isometric force (p = 0.015; d = 0.30). After the isometric fatigue task, the DSI increased, indicating a more substantial decline in isometric force (p < 0.001; d = 1.75) compared to dynamic force (p = 0.313; d = 0.08). Following this trend, the DSI decreased post-dynamic fatigue (p < 0.001; d = 0.99) and increased post-isometric fatigue (p < 0.001; d = 3.11). Conclusion: This research underscores the need to consider fatigue’s task-specific effects on the DSI, enabling more tailored training methodologies for athletes.

Recently, the transient characteristics of postural sway have been suggested as an alternative or an improvement to traditional whole-trial analyses, possibly reflecting the sensory reweighing process. The purpose of this study was to assess if the transient characteristics of postural sway are sensitive to age and postural tasks. Twenty young adults (18–27 years old) and fifteen older adults (67–80 years old) performed parallel (eyes open and eyes closed), tandem and single-leg postural tasks for 30 s. Centre of pressure (CoP) velocity, amplitude and frequency were derived from force plate data. In addition to whole-trial estimates, we calculated the relative differences between the 1st and the 2nd (DIF_21) and the 1st and the 3rd (DIF_31) 10 s time intervals. Postural sway increased with the difficulty of the task, and the increase was more pronounced in the older adult group (p < 0.001; η2 = 0.31–0.38 for group × task interactions). Large and statistically significant age × task interactions were shown for both DIF_21 and DIF_31 for CoP anterior–posterior frequency (p < 0.001; η2 = 0.17–0.18). Possible age differences were also indicated for the transient response in CoP medial–lateral velocity in the parallel stance task. Specifically, we found an exaggerated transient response (i.e., relatively higher COP velocity in the first 10 s) in older adults compared to young adults when visual information was restored during the parallel quiet stance. This study shows the potential for an application of measures of the transient behavior of postural sway after the removal or restoration of visual information.

Achilles tendinopathy (AT) is the most common injury of the Achilles tendon and represents 55–65% of all Achilles tendon clinical diagnoses. AT is characterized by pain, swelling, and impaired performance. ATs can be divided into two types, according to anatomical location—midportion AT (MAT) and insertional AT (IAT). MAT more often occurs in older, less active, and overweight populations, while IAT usually occurs in the more physically active population. Both types of AT can be treated by different treatments, such as surgery, conservative pharmacological treatments, and conservative nonpharmacological treatments. This umbrella review aims to assemble the evidence from all available systematic reviews and/or meta-analyses to determine which conservative nonpharmacological treatments are most commonly used and have the greatest effects. Three major electronic scientific databases (PubMed, Scopus, and Web of Science) were screened. The reference lists of several recent articles on AT were also searched. We found 50 articles that met the inclusion criteria. The methodological quality of the included articles was assessed using the AMSTAR 2 tool. Eccentric (ECC) exercise, isotonic (ISOT) exercise, and acupuncture treatment showed the greatest effects for treating MAT as a standalone therapy. Meanwhile, extracorporeal shockwave therapy and ECC exercise provided the best outcomes for treating IAT as individual treatments. However, an even greater pain decrease, greater function improvement, and greater patient satisfaction for treating either MAT or IAT were achieved with combined protocols of ECC exercise with extracorporeal shockwave therapy (in both cases), ECC exercise with cold air and high-energy laser therapy (in the case of IAT), or ECC exercise with ASTYM therapy (in the case of IAT).

The reactive strength index (RSI) is used to assess reactive strength in the lower limbs. Since previous studies have mostly focused on vertical RSI (derived from drop jumps), we investigated the RSI across eight consecutive unilateral horizontal hops and its associations with sprint performance. A sample of 104 male kinesiology students (age: 19.2 ± 1.1 years) performed unilateral hops and 100 m sprints with split times recorded. RSI was determined as the ratio between contact time and subsequent flight time for each hop. On a group level, the horizontal RSI was statistically significantly (p < 0.001; ηp2 = 0.49) and increased from hop 1 (1.04 ± 0.17) to hop 5 (1.41 ± 0.22), but then plateaued (1.43–1.44) for hops 6–8. However, on an individual level, variations in RSI were present all the way to the last hop. All sprint split times were in small-to-moderate correlation with RSI variables (r = 0.25–0.40), implying that individuals with higher hopping RSI presented with shorter sprint times. Future studies should expand the research on the relationship between horizontal hopping RSI and sports performance, and examine if unilateral RSI tests can provide practitioners with valuable information when performed alongside more common vertical RSI tests.

Background: The rate of force development (RFD) is a measure of explosive strength, commonly evaluated within the same repetition as peak force/torque, by instructing the participants to produce “fast” and “hard” contraction. Previous studies have indicated that attempting to achieve the maximal RFD and maximal force/torque within the same contraction may not be optimal. Methods: This study assessed the differences between explosive sustained (“fast-and-hard”) and ballistic (pulse-like) contractions on the RFD during isometric ankle and knee extensions in young, recreationally active participants (n = 33; age: 23.4 ± 5.6 years). The participants performed both contraction types for isometric ankle and knee extension tasks. The RFD was calculated for time intervals 50, 100, 150 and 200 ms from the contraction onset and also in between these time points (50–100, 100–150 and 150–200 ms). Findings: The results of this study showed a higher RFD in the ballistic contractions in later time intervals (100–150 and 150–200 ms) compared to that of the explosive sustained contractions (effect size (Hedge’s g) = 0.51–0.73). The differences between explosive sustained and ballistics contractions were larger and occurred for more outcome variables in females than males. Peak RFD was also larger in ballistic contractions, both for females (p = 0.010; Hedge’s g = 0.54) and males (p = 0.003; Hedge’s g = 0.78). The intra-session reliability of the RFD was similar for both contraction types, increasing from moderate to excellent with longer time intervals. Conclusion: Our results suggest that ballistic contractions should be used when the assessment of the RFD is the primary goal. When the aim is to assess both the RFD and peak force, it is suggested to use the combination of separate explosive sustained contractions and ballistic contractions in the protocol.

Rate of force/torque development scaling factor (RFD-SF/RTD-SF) has been used as a tool for assessing neuromuscular quickness. The aim was to investigate strength capacities of two major shooting muscle groups and their relationship to basketball shooting performance, and to compare the RFD-SF as well as shooting performance between junior and senior basketball players, and finally to examine the differences in RTD-SF between elbow extensors and volar flexors. In 23 male basketball players (13 juniors and 10 seniors) we assessed maximal isometric torque (TMVC), maximal rate of torque development and RTD-SF slope (kRTD-SF) for elbow extensors and volar flexors. The subjects performed 10 throws at 2.3 m (short) and 8.9 m (long) from the basket. Our results showed similar kRTD-SF and TMVC in both groups. Better shooting performance from short distance was observed in senior players. Significant associations between kRTD-SF, TMVC and shooting performance were found only in juniors. Elbow extensors TMVC was found to have a significant positive large association with shooting performance from long distance. It seems that muscle capacity has an important role in shooting performance in junior compared to players. Sufficient strength capacity of major shooting muscles is important for juniors’ shooting performance from a long distance.