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Context: The evaluation of quadriceps muscle inhibition with the interpolated twitch technique is usually performed by stimulating the femoral nerve (FN). However, there are some problems related to the use of this stimulation site, which may be partially overcome by delivering the stimulation over the motor point (MP). This study sought to compare MP to FN stimulation at different joint angles for the evaluation of quadriceps muscle inhibition, resting peak torque, and discomfort in healthy women. Design: Cross-sectional study. Methods: Sixteen healthy women (age: 28 [4] y; body mass: 60 [5] kg; height: 162 [5] cm) participated in this study. Supramaximal paired stimuli were delivered to the FN and to the rectus femoris MP before and during maximal voluntary contractions at different knee angles (15°, 30°, 45°, 60°, and 90° of knee flexion) to assess muscle inhibition and resting peak torque. Discomfort was also recorded for each stimulation site and knee angle. Results: Muscle inhibition was similar between the 2 stimulation sites (P >.05) and was higher at 45° than at 90° (P =.03). MP stimulation evoked lower resting peak torque at 30° (P =.004), 60° (P =.006), and 90° (P =.006) and higher discomfort at 30° (P =.008) and 90° (P =.027) compared to FN stimulation. Conclusions: Despite lower resting peak torque and higher discomfort at some angles, MP stimulation provided similar muscle inhibition to FN stimulation at all knee angles and is therefore a valid method to evaluate quadriceps muscle inhibition in healthy women. MP stimulation can be used as an alternative to FN stimulation for the evaluation of quadriceps muscle inhibition with no added discomfort at the angles where muscle inhibition is the highest. [ABSTRACT FROM AUTHOR]

Background: Hip and groin problems are common among team-sport athletes. However, few studies have been conducted in female athletes that have used the Doha Agreement classification system to categorize these problems. Purpose: The purpose of this study was to examine the preseason point prevalence of hip and groin problems in elite female team-sport athletes. Secondary aims were to categorize the groin problems according to the Doha Agreement classification system and to explore the association between hip muscle strength and self-reported hip and groin function. Study Design: Cross-sectional study. Methods: Female athletes who participated in various sports underwent preseason assessment of isometric hip adduction and abduction strength, with pain levels recorded during respective contractions, and self-reported function on the Copenhagen Hip and groin Outcome Score (HAGOS). If any athlete reported current hip and groin problems during this screening assessment, a full, standardized clinical hip and groin examination was undertaken. These hip and groin problems were then categorized according to the Doha Agreement classification system. Comparisons between the participants with vs without hip and groin problems were made, and correlational statistics were used to examine relationships between strength and HAGOS scores. Results: Ninety-one elite female athletes from six different sports were included in the study. Thirteen athletes reported current hip and groin problems, with an overall prevalence rate of 14.3%. Iliopsoas-related groin pain was the most common category diagnosed, accounting for 58.8% of cases, followed by hip-related groin pain (17.6%), adductor-related (11.8%), and inguinal- and pubic-related pain (both 5.9%). No association was found between strength and function. Conclusion: The hip and groin point prevalence in female athletes documented during preseason appears to be similar to those reported in male athletes. Iliopsoas-related groin pain was the most common clinical entity reported in female athletes in this study. There was no association between hip muscle strength and self-reported hip and groin function. Level of Evidence: 3b [ABSTRACT FROM AUTHOR]

Context: Injury prevention programs for the lower extremities are effective in team-sport athletes. Objective: To identify barriers and facilitators among professional ice hockey players and staff members for adhering to an injury prevention program. Design: Cross-sectional survey. Setting and Participants: A questionnaire about barriers and facilitators related to knowledge/perceptions, beliefs, adoption, and habits about injury prevention was filled out by Swiss professional male ice hockey players and staff members. Main Outcome Measures: Frequencies of ratings were calculated and binary logistic regression analysis was applied to predict a relationship between a high/low perceived benefit of an injury prevention program and player characteristics. Results: Knowledge, perceived benefit, and relevance of injury prevention as well as awareness of high risk of injuries in ice hockey were identified as important facilitators. Players' habit of exercise performance was identified as a barrier. Program understanding of staff members was identified as a facilitator and barrier. No significant relationships were observed between a high/low perceived benefit of an injury prevention program and age (P =.85), nationality (P =.53), level of education (P =.63), National League experience (P =.50), or occurrence of lower-extremity injuries in the previous season (P =.10). Conclusions: Players and staff members clearly rated perceived benefits of an injury prevention program, which can be considered an important facilitator of the uptake and adoption of such a program in ice hockey teams. Players should be educated about well-performed injury prevention exercises. Staff members should be educated about the aim of a regular injury prevention program. An injury prevention program might be implemented in players of all ages, levels of education, and experience in the National League, irrespective of previous injuries. Identified barriers and facilitators should be addressed when implementing an injury prevention program in a setting of professional ice hockey teams in the future. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of different modalities of morning priming exercise on afternoon physical performance with the associated hormonal and psychophysiological responses in young soccer players. Methods: In a randomized counterbalanced crossover design, 12 young soccer players completed 3 different morning conditions on 3 different days: repeated-sprint running (6 x 40 m), easy exercise (4 x 12 fast half squats, 6 speed ladder drills, and 20-m sprints), and control (no exercise). Blood testosterone and cortisol concentrations were assessed upon arrival (approximately 8:30AM) and approximately 5 hours and 30 minutes later. Body temperature, self-reported mood, quadriceps neuromuscular function (maximal voluntary contraction, voluntary activation, rate of torque development, and twitch contractile properties), jump, and sprint performance were evaluated twice per day, while rating of perceived exertion, motivation, and the Yo-Yo Intermittent Recovery level 2 (IR2) tests were assessed once per day. Results: Compared with the control, repeated-sprint running induced a possible positive effect on testosterone (+11.6%) but a possible to very likely negative effect on twitch contractile properties (-13.0%), jump height (-1.4%), and Yo-Yo IR2 (-7.1%). On the other hand, easy exercise had an unclear effect on testosterone (-3.3%), resulted in lower self-reported fatigue (-31.0%) and cortisol (-12.9%), and had a possible positive effect on the rate of torque development (+4.3%) and Yo-Yo IR2 (+6.5%) compared with the control. Conclusions: Players' testosterone levels were positively influenced by repeated-sprint running, but this did not translate into better physical function, as both muscular and endurance performance were reduced. Easy exercise seemed to be suitable to optimize the physical performance and psychophysiological state of young soccer players. [ABSTRACT FROM AUTHOR]

The main aims of this study were to compare the magnitude of inter-limb asymmetry (ILA) and the relation with self-reported knee function between maximal and explosive knee extensor strength outcomes in professional soccer players. Forty-six male soccer players completed different maximal isokinetic and isometric contractions of the knee extensors for the assessment of maximal strength (peak torque and maximal voluntary contraction (MVC) torque) and explosive strength (early, intermediate, late, and peak rate of torque development (RTD)). Self-reported knee function was assessed with the International Knee Documentation Committee (IKDC) and Lysholm knee scoring scales. Peak torque and MVC torque showed comparable ILAs (8-9%), both being significantly lower than all RTD ILAs (16% on average; p < 0.001). ILAs for early RTD (21%) and peak RTD (19%) were significantly higher than all the other variables (p < 0.05). Only early and intermediate RTD were significantly correlated – though weakly – with both IKDC (rho = 0.32 for both) and Lysholm (rho = 0.36 and 0.30, respectively) scores. We conclude that explosive knee extensor strength – early RTD in particular – exhibited larger ILAs and better relations with self-reported knee function than peak torque and MVC torque in professional soccer players. These results confirm the validity and functional relevance of early RTD and the need for its inclusion in routine performance testing for soccer players. Highlights Professional soccer players exhibited larger inter-limb deficits in knee extension strength for explosive actions than for the widely-used isokinetic test. Self-reported knee function was significantly correlated with explosive strength of the knee extensor muscles but not with maximal strength. The first 50 ms of an explosive knee extension seem to be crucial for self-perceived sport performance and possibly for injury prevention. [ABSTRACT FROM AUTHOR]