Matthew D. DeLang

The COVID-19 lockdown challenged the training options of athletes worldwide, including players from the most popular sport globally, football/soccer. Purpose: The authors explored the training practices of football players worldwide during the COVID-19 lockdown. Methods: Football players (N = 2482, 30% professional, 22% semipro, and 48% amateur) completed an online survey (May–July 2020) on their training practices before versus during lockdown (March–June 2020). Questions were related to training frequency and session duration, as well as training knowledge and attitudes. Results: Before lockdown, more professional (87%) than semipro (67%) and amateur (65%) players trained ≥5 sessions/wk, but this proportion decreased during the lockdown to 55%, 35%, and 42%, respectively. Players (80%–87%) trained ≥60 minutes before lockdown, but this proportion decreased to 45% in professionals, 43% in amateurs, and 36% in semipros during lockdown. At home, more than two-thirds of players had training space (73%) and equipment (66%) for cardiorespiratory training, while availability of equipment for technical and strength training was Conclusion: COVID-19 lockdown negatively affected training practices of football players worldwide, especially amateurs and semipros, for example, in training frequency, duration, intensity, technical, recovery, and other fitness training and coaching-related aspects. During lockdown-like situations, players should be monitored closely and provided appropriate support to facilitate their training.

Introduction Groin monitoring systems are a secondary prevention tool in youth football. Symptom screenings can be supported by objective findings, such as hip adduction squeeze strength. This study examined how groin pain influenced weekly squeeze strength in youth academy football players over a 14-week period. Materials and Methods Weekly monitoring of youth football players consisted of groin symptom check-ins and long lever squeeze strength. Players who reported groin pain were stratified into the groin pain group while players who did not report pain remained in the no groin pain group. Baseline squeeze strength was retrospectively compared between the groups. Players with groin pain were examined via repeated measures ANOVA at four timepoints: baseline, one-week-prior to pain onset, pain onset, and return to pain-free. Results 53 players were included (age 14.4±1.6 years). Baseline squeeze strength was not different between players in the groin pain (n=29, 4.35±0.89 N/kg) versus no groin pain group (n=24, 4.33±0.90 N/kg, p=0.83). Players with no groin pain maintained similar squeeze strength throughout 14 weeks (p>0.05). Compared to baseline (4.33±0.90 N/kg), players with groin pain had decreased squeeze strength at one-week-prior to pain onset (3.91±0.85 N/kg, p=0.003) and at pain onset (3.58±0.78 N/kg, pConclusion Decreases in groin squeeze strength exist in players with groin pain onset, and even manifest one-week prior to groin pain onset, compared to players without groin pain. Weekly squeeze strength may be an early marker for groin pain.

Objective: To (1) systematically screen for groin pain and type in young elite soccer players and (2) assess whether hip and groin-related severity and disability differed between players with different levels of groin pain and tenderness. Design: Cross-sectional observational. Setting: Elite American soccer academy at midseason. Participants: One hundred one academy soccer players (mean age 14.3 ± 1.8 years). Intervention: All players underwent clinical examinations to classify groin pain by the Doha agreement taxonomy. Main Outcome Measures: Tests for groin-related severity and disability included the Copenhagen 5-second squeeze test, Copenhagen Hip and Groin Outcome Score (HAGOS), and Hip Outcome Score (HOS). Players were stratified into 3 groups: those with groin pain, those with tenderness, and those with no groin pain or tenderness. Results: Twenty-two players (22%) reported groin pain. Adductor-related groin pain was the most common (n = 14), followed by iliopsoas-related (n = 3), and pubic-related (n = 2). Multiple locations were present in 3 players. Thirty-nine players (39%) did not have groin pain but were tender to palpation in 1 or more structures related to the Doha agreement taxonomy. Copenhagen 5-second squeeze test differentiated between players with and without groin pain (groin pain vs tenderness group: P = 0.011; groin pain vs no groin pain group P < 0.001). Four HAGOS subscales (pain, symptoms, sport/recreation, and quality of life) differentiated between players with and without groin pain (P < 0.05). Conclusions: One in five academy soccer players experiences groin pain with adductor-related most common during a midseason screening. Both Copenhagen 5-second squeeze test and HAGOS subscales can differentiate between players with and without groin pain.

Background The month of Ramadan will intersect with many football leagues’ schedules over the next decade. Understanding the effects of Ramadan intermittent fasting (RIF) on physical performance is necessary to guide considerations for football players. Objective The aim of this systematic review was to investigate the effects of RIF on physical factors in football players, and secondarily to consider the impact this may have on domestic club football leagues. Design We conducted a systematic review using PRISMA guidelines. Data Sources The online literature search utilized CINAHL (EBSCO), Cochrane Library, Embase.com, PubMed, and Scopus databases, and grey literature (all from database inception to May 2020). Study Selection Criteria Inclusion criteria consisted of studies of football (soccer) players, data collected during and/or around Ramadan, with injury and/or performance data provided. Results The search yielded 11,226 studies. Twenty-two studies were included following a review of titles, abstracts, and full texts. Studies included some iteration of before-Ramadan, during-Ramadan, and after-Ramadan data. Common measures observed included ratings of perceived exertion (n = 8), sprinting (n = 7), sleep (n = 7), peak heart rate (n = 6), jumping (n = 5), Yo-Yo intermittent recovery tests (n = 4), Wingate anaerobic test (n = 3), field-specific tests (n = 3), and injury rates (n = 2). Decreased physical performance was commonly observed during late afternoon/evening testing (before breaking the fast) and with high-intensity exercise. Conclusion There appears to be a performance deficit related to RIF in Muslim football players. Studies should explore the effects of RIF on actual match demands. Due to the month of Ramadan emerging into league calendars, considerations should be made to accommodate Muslim football players who are intermittently fasting.

Background: Multiplanar dynamic stability is an important unilateral function in soccer performance but has been scarcely examined in female soccer players. The lateral vertical jump task assesses unilateral functional performance, and energy generation contribution examines how each joint (hip, knee, ankle) contributes to the vertical component of the vertical jump phase to measure inter- and intra-limb differences. Purpose: To examine dominant versus non-dominant limb performance using energy generation contribution of the hip, knee, and ankle during the vertical jump component of the lateral vertical jump. Study Design: Cross-sectional observational study. Methods: Seventeen healthy, adolescent female soccer players (age 13.4±1.7 years; height 160.6±6.0 cm; mass 53.1±8.2 kg) participated. Quadriceps strength was measured via isokinetic dynamometry. Energy generation contribution (measured from maximal knee flexion to toe off) and vertical jump height were measured during the vertical component of the lateral vertical jump. Results: There was no significant difference between limbs for quadriceps strength (p=0.64), jump height (p=0.59), or ankle energy generation contribution (p=0.38). Energy generation contribution was significantly greater in the dominant hip (dominant 29.7±8.6%, non-dominant 18.4±6.3%, p<0.001) and non-dominant knee (dominant 22.8±6.8%, non-dominant 36.2±8.5%, p<0.001). Conclusion: High demand on coordination and motor control during the lateral vertical jump and inherent limb dominance may explain different intra-limb strategies for task performance despite jump height symmetry. Non-dominant affinity for stability and dominant compensatory performance may neutralize potential asymmetries. Implications for symmetry in observable outcomes such as jump height must consider underlying internal asymmetries. Levels of Evidence: 3B Clinical Relevance: Symmetrical findings on functional tasks have underlying internal asymmetries observed here in female adolescent soccer players. The lateral vertical jump may highlight these internal asymmetries (hip- versus knee-dominant movement strategies) due to the high coordinative demand to perform the task. Clinicians should be cognizant of underlying, potentially inherent, asymmetries even when observing functional symmetry in a task. What is known about the subject: Female adolescent soccer players are a high-risk cohort for sustaining anterior cruciate ligament injuries. Limb dominance may play a role in the performance of functional tasks, and limb dominance in soccer players is quite specialized: the dominant limb is the preferred kicking limb, while the non-dominant limb is the preferred stabilizing limb (plant leg). Functional performance in female soccer players has been studied in kicking, dribbling, sprinting, change of direction, and jumping – however, these tasks were measured independent of limb dominance. It remains to be seen how unilateral functional tasks may be affected by limb dominance in female adolescent soccer players. What this study adds to existing knowledge: This study provides data on functional performance relative to limb dominance in female adolescent soccer players, and captures the lateral vertical jump task in both inter- and intra-limb measures. This highlights that intra-limb strategies to perform a coordinated motor task may be different between limbs, herein attributed to limb dominance. Even if gross motor outputs between limbs are symmetrical (i.e. jump height), the underlying movement strategies to achieve that output may be different (hip- versus knee-dominant movement strategies). These findings are important to research on functional performance measures related to attaining between-limb symmetry, as measures of energy generation contribution open the door for a more thorough understanding of joint-by-joint intra-limb contributions during a functional task.

Injury prevention strategies in team settings should not overlook early detection and secondary prevention. Monitoring systems may be an effective approach to detect common and troublesome injuries, such as hip and groin pain in football (soccer) players. The purpose of this International Perspective is to share our experiences with monitoring hip and groin pain in youth academy football and discuss challenges that surfaced. We consider why players may not accurately report pain, their perceptions of groin pain, and whether all groin pain is clinically meaningful. Level of Evidence: 5

In soccer (football), dominant limb kicking produces higher ball velocity and is used with greater frequency than the non-dominant limb. It is unclear whether limb dominance has an effect on injury incidence. The purpose of this systematic review with meta-analysis is to examine the relationship...