Effects of Consecutive Matches on Isometric Hamstring Strength, Flexibility Values and Neuromuscular Performance in Female Field Hockey Players. A Prospective, Observational Study  
[PERSON]  
1 Exercise Physiology Group, School of Physiology, Faculty of Health Sciences, Universidad Francisco de Vitoria, 28049 Madrid, Spain; violeta.smigallon@uvfes (V.S.-M.); alvaro.lopez@uvfes (A.L.-S.); vicente.fernandez@uvfes (V.F.-R.); [EMAIL_ADDRESS] (S.G.); josebernardo.diazmaroto@uvfes (J.B.D.-M.)  
[PERSON]  
2 Center for Translational Research in Physiotherapy, Department of Pathology and Surgery, Universidad Miguel Hernandez, 03202 EIche, Spain; [EMAIL_ADDRESS]  
[PERSON]  
1 Exercise Physiology Group, School of Physiology, Faculty of Health Sciences, Universidad Francisco de Vitoria, 28049 Madrid, Spain; violeta.smigallon@uvfes (V.S.-M.); alvaro.lopez@uvfes (A.L.-S.); vicente.fernandez@uvfes (V.F.-R.); [EMAIL_ADDRESS] (S.G.); josebernardo.diazmaroto@uvfes (J.B.D.-M.)  
[PERSON]  
1 Exercise Physiology Group, School of Physiology, Faculty of Health Sciences, Universidad Francisco de Vitoria, 28049 Madrid, Spain; violeta.smigallon@uvfes (V.S.-M.); alvaro.lopez@uvfes (A.L.-S.); [PERSON]@uvfes (V.F.-R.); [EMAIL_ADDRESS] (S.G.); josebernardo.diazmaroto@uvfes (J.B.D.-M.  
match can induce muscle damage and post-match fatigue that can last up to seventy-two hours [6]. This has resulted in a reduction in the ability to maintain high speeds and in the number of accelerations/minute [7], being attributed to peripheral fatigue appearance due to depletions in muscle glycogen concentrations [8]. As a result, limited recovery time between matches increases residual fatigue and consequently increases the risk of injury [9], as evidenced by epidemiological research. Research has shown higher injury rates in competitions where there were four or fewer days of recovery when compared to competitions with six or more days of recovery [10].  
Furthermore, epidemiological research has shown that the lower limbs are the most affected by injuries in field hockey, with the hamstring strain injury being one of the most frequent muscle injuries [11]. Hamstring injuries are common in other intermittent sports, occurring during maximal or sub-maximal sprinting [12] when there is constant, repetitive stress placed on these muscles when the fibers are rapidly lengthened and contracted during the sprint cycle [13]. Since previous research in similar intermittent sports has shown that the incidence of such injuries is higher during matches [14], playing consecutive games with insufficient recovery can not only affect physical performance but can also increase the injury risk. To implement preventive strategies, the identification of risk factors, both intrinsic and extrinsic, associated with hamstring injury occurrence is crucial. These include: age [15], previous injury [16], hamstring strength [17; 18; 19], decreased range of knee extension [20; 21], and ankle dorsiflexion [22; 23]. Specifically, in the case of an intermittent sport such as field hockey, fatigue has been linked to a decrease in hamstring strength values, and this is an important risk factor for a hamstring injury [24]. Moreover, an incomplete recovery could lead to lower strength values in the hamstrings [25]. Despite the relevance of cumulative fatigue on the hamstring musculoskeletal characteristics of athletes, the effect of consecutive matches on hamstring injury risk factors has not yet been examined in field hockey players during the accumulation of several matches. Therefore, this study aimed to examine the effects of two consecutive official league field hockey matches, played within 24 h, on lower-limb risk factors of hamstring injuries such as isometric knee flexion strength, passive hip flexion [21], and ankle dorsiflexion range of motion [26]. Based on previous research, it was hypothesized that the registered values for these variables will reduce over the duration of the matches and recover partially 48 h after the 2 nd match.