Hamstring injury prevention in soccer: Before or after training?

We examined the effects of a 12‐week program of Nordic hamstring exercises (NHE ), administered before or after football training, upon eccentric hamstring strength, muscle activity, and architectural adaptations. Amateur soccer players were randomized into three groups. The control group (CON ; n=11) undertook core stability exercises, whereas a periodized NHE program was delivered either before (NHE_BEF ; n=10) or after (NHE_AFT ; n=14) biweekly training sessions. Outcome measures included peak torque and concomitant normalized peak surface electromyography signals (sEMG ) of the biceps femoris (BF ) and medial hamstring (MH ) muscles during knee flexor maximal eccentric contractions, performed at 30°·s⁻¹. Ultrasonography was used to determine BF muscle thickness, muscle fiber pennation angle, and fascicle length. Performing the NHE derived likely moderate peak torque increases in both NHE_BEF (+11.9%; 90% confidence interval: 3.6%‐20.9%) and NHE_AFT (+11.6%; 2.6%‐21.5%) vs CON . Maximum sEMG increases were moderately greater in the BF of both NHE training groups vs CON . There were likely moderate increases in BF muscle thickness (+0.17 cm; 0.05‐0.29 cm) and likely small pennation angle increases (+1.03°; −0.08° to 2.14°) in NHE_AFT vs CON and NHE_BEF . BF fascicle length increases were likely greater in NHE_BEF (+1.58 cm; 0.48‐2.68 cm; small effect) vs CON and NHE_AFT . A 12‐week eccentric hamstring strengthening program increased strength and sEMG to a similar magnitude irrespective of its scheduling relative to the football training session. However, architectural adaptations to support the strength gains differed according to the timing of the injury prevention program.     

Self‐regulatory skills: Are they helpful in the prevention of overuse injuries in talented tennis players?

Talented athletes use metacognitive skills to improve their performance. Also, it is known that these skills are important for managing one's health. The goal of this study was to identify the relationship between metacognitive skills and overuse injuries in talented tennis players. Metacognitive skills were measured in 73 talented tennis players (45 boys and 28 girls, age 11‐14) at the start of the season, using the Self‐Regulation of Learning Self‐Report Scale. Overuse injuries were monitored for one season using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Ordinal regression indicated that moderate or low selfmonitoring skills (compared to high selfmonitoring) (OR 4.555, CI 1.096‐18.927, P = 0.037) and exposure time (OR 1.380, CI 1.106‐1.721, P = 0.004) were associated with more time loss overuse injuries. A second analysis showed that this was the case in girls (OR 10.757, CI 1.845‐62.714, P = 0.008), but not in boys. Linear regression revealed that higher reflection scores and exposure time predicted overuse severity (F(5,58) = 2.921, P = 0.020, R² = 0.201). Possibly, selfmonitoring can help players to prevent themselves from time loss overuse injuries. Coaches should be aware that players can differ in selfmonitoring ability and thus in the ability to prevent overuse injuries. The role of reflection needs more research.     

Examination of the external and internal load indicators’ association with overuse injuries in professional soccer players

Objectives

Research in professional soccer focusing on the relevance of external and internal load indicators for injury prevention is scarce. This study examined the relationship between load indicators and overuse injuries.

Weight status and physical fitness in female soccer players: is there an optimal BMI?

The aim of this study was to examine the relationship between weight status and physical fitness in female soccer players. For this purpose, 54 soccer players [21.7 (4.0) years, 60.5 (7.0) kg, 164.3 (4.7) cm, mean (standard deviation)] underwent a physical fitness battery. To study this relationship we used a correlation analysis and compared three groups differing in body mass index (BMI): group A (BMI < 21 kg m^?2), B (21 < BMI < 23 kg m^?2) and C (BMI > 23 kg m^?2). We found very large correlations between BMI and the components of somatotype (0.70 ≤ |r| ≤ 0.92, p < 0.001). BMI was also correlated with isometric muscle strength and leg muscle power (W) assessed by the Wingate anaerobic test (WAnT) and force–velocity test. In contrast, when muscle power was expressed as W kg^?1, the correlation was negative. We also found an inverse relationship between BMI and fatigue index of WAnT (r = 0.36, p < 0.05): the higher the BMI, the higher was the decrease in performance during this 30 s all-out test. The comparison between A, B and C groups revealed differences in the same direction as the correlation analysis. We concluded that weight status is closely related with body composition, somatotype and leg muscle power. Therefore, achieving an optimal BMI might result in improvements with regard to physique and anaerobic power, and consequently in performance enhancement.     

Scheduling of eccentric lower limb injury prevention exercises during the soccer micro‐cycle: Which day of the week?

Scheduling eccentric‐based injury prevention programs (IPP ) during the common 6‐day micro‐cycle in soccer is challenged by recovery and tapering phases. This study profiled muscle damage, neuromuscular performance, and perceptual responses to a lower limb eccentric‐based IPP administered 1 (MD +1) vs 3 days (MD +3) postmatch. A total of 18 semi‐professional players were monitored daily during 3 in‐season 6‐day micro‐cycles, including weekly competitive fixtures. Capillary creatine kinase concentration (CK ), posterior lower limb isometric peak force (PF ), counter‐movement jump (CMJ ) performance, and muscle soreness were assessed 24 hours prior to match‐day (baseline), and every 24 hours up to 120 hours postmatch. The IPP consisted of lunges, single stiff leg dead‐lifts, single leg‐squats, and Nordic hamstring exercises. Performing the IPP on MD +1 attenuated the decline in CK normally observed following match play (CON : 142%; MD +3: 166%; small differences). When IPP was delivered on MD +3, CK was higher vs CON and MD +1 trials on both MD +4 (MD +3: 260%; CON : 146%; MD +1: 151%; moderate differences) and MD +5 (MD +3: 209%; CON : 125%; MD +1: 127%; small differences). Soreness ratings were not exacerbated when the IPP was delivered on MD +1, but when prescribed on MD +3, hamstring soreness ratings remained higher on MD +4 and MD +5 (small differences). No between‐trial differences were observed for PF and CMJ . Administering the IPP in the middle of the micro‐cycle (MD +3) increased measures of muscle damage and soreness, which remained elevated on the day prior to the next match (MD +5). Accordingly, IPP should be scheduled early in the micro‐cycle, to avoid compromising preparation for the following match.     

The effect of the time-of-day of training during Ramadan on soccer players’ chronotype and mood states

The aim of the present study was to investigate the effect of time-of-day of training during Ramadan on soccer players’ chronotype and mood states. Thirty participants were randomly assigned to either a morning training group (MTG, trained between 0700 and 0830 hours, n = 10), an evening training group (ETG, trained between 1700 and 1830 hours, n = 10), or a control group (CG, did not train, n = 10). They completed two questionnaires before (BR) and at the end of (ER) Ramadan: the Horne and Östberg’s self-assessment questionnaire and the Profile of Mood States (POMS) questionnaire. The results showed that the MTG maintained the Horne and Östberg’s scores during ER compared with BR, with all players classified as “moderately morning type”. However, Horne and Östberg’s scores were reduced in the ETG (p < 0.05), with all players classified as “moderately evening type”, and in the CG, with six players classified as “neither type” and four as “moderately evening type”. There was not a significant effect of Ramadan on mood states. Only fatigue was increased and vigor was reduced in the ETG. Therefore, morning training did not affect the chronotype of the players during Ramadan. However, evening training reduced the Horne and Östberg’s scores. During ER, the participants of the MTG were classified as “moderately morning type” and the participants of the ETG were classified as “neither type” (n = 6) and “moderately evening type” (n = 4).     

Does kinesiology taping of the ankles affect proprioceptive control in professional football (soccer) players?

ObjectiveTo determine whether the bilateral application of kinesiology tape (KT) to professional footballers' ankles can improve their lower limb proprioception.DesignA single blind randomised crossover study. Participants were randomly assigned to complete a proprioception test in either a taped or not taped condition first. Following a wash out period, participants were then re-tested in the alternate condition.SettingA UK Championship League Football Club, mid-season.ParticipantsTwenty male professional football players over the age of 18, currently match fit with no injuries.Outcome measureProprioception was assessed by participants undertaking the moving target program on the balance module attached to a Kin-Com 125AP isokinetic dynamometer. A paired sample two tailed t-test was used to assess whether there was a significant difference between the participants test scores in the not taped and taped conditions.ResultsThe bilateral application of KT to professional footballers' ankles did not bring about a significant change in participants' scores when tested with a fine movement and balance control test. Percentage accuracy score mean difference 4.2 (p = 0.285).ConclusionThe results of this study do not support the use of KT when applied to the ankles of healthy footballers as a method of improving proprioception.     

Is lin28a polymorphism associated with endurance performance in soccer players?

Sport Sciences for Health - The aim of this study was to investigate the association of rs6598964 (A?&gt;?G), a molecular marker located in the LIN28A gene, with the performance of...