Association between lower extremity muscle strength and acute ankle injury in youth team-sports athletes

OBJECTIVES

To investigate lower extremity muscle strength as risk factor for an acute ankle injury in youth athletes.

DESIGN

Cohort study.

SETTING

Basketball and floorball clubs.

PARTICIPANTS

188 youth (≤21) male and 174 female athletes.

MAIN OUTCOME MEASURES

1RM leg press, maximal concentric isokinetic quadriceps and hamstrings as well as maximal isometric hip abductor strength were measured and athletes were followed for an acute ankle injury up to three years. Cox regression models were used in statistical analyses.

RESULTS

In males, greater 1RM leg press and maximal quadriceps strength increased the risk of any type of acute ankle injury (Hazard ratio [HR] for 1 SD increase, 1.63 [95% CI, 1.12-2.39] and 1.43 [95% CI, 1.01-2.01], respectively). In females, greater 1RM leg press and difference between legs in hip abduction strength increased the risk of acute non-contact ankle injury (HR for 1 SD increase, 1.44 [95% CI, 1.03-2.02] and 1.44 [95% CI, 1.03-2.00], respectively). However, ROC curve analyses showed AUC:s of 0.57-0.64 indicating "fail" to "poor" combined sensitivity and specifity of these tests.

CONCLUSION

Greater strength in both sexes along with asymmetry in hip abductor strength in females increased the risk of acute ankle injury.

Knee function among elite handball and football players 1-6 years after anterior cruciate ligament injury

The aim of the study was to describe objective and self-reported knee function for athletes who have returned to elite handball and football play after an ACL injury, comparing these to non-injured players at the same level. A total of 414 handball and 444 football players completed baseline tests from 2007 through 2014, examining lower extremity strength, dynamic balance, knee laxity, and knee function (KOOS questionnaire). Measures were compared between injured and non-injured legs and between injured legs and legs of controls. Eighty (9.3%) of the 858 players reported a previous ACL injury, 1-6 years post-injury (3.5±2.5 years), 49 handball (61.3%) and 31 football players (38.7%). We found no difference in strength or dynamic balance between previously ACL-injured (N=80) and non-injured players legs (N=1556). However, lower quadriceps (6.3%, 95% CI: 3.2-9.2) and hamstrings muscle strength (6.1%, 95% CI: 3.3-8.1) were observed in previously ACL-injured legs compared to the non-injured contralateral side (N=80). ACL-injured knees displayed greater joint laxity than the contralateral knee (N=80, 17%, 95% CI: 8-26) and healthy knees (N=1556, 23%, 95% CI: 14-33). KOOS scores were significantly lower for injured knees compared to knees of non-injured players. ACL-injured players who have successfully returned to elite sport have comparable strength and balance measures as their non-injured teammates. Subjective perception of knee function is strongly affected by injury history, with clinically relevant lower scores for the KOOS subscores Pain, Function, Sport, and Quality Of Life.

Self-reported psychological characteristics as risk factors for injuries in female youth football

Identifying and understanding injury risk factors are necessary to target the injury-prone athlete and develop injury prevention measurements. The influence of psychological factors on injuries in football is poorly documented. The purpose of this 8-month prospective cohort study therefore was to examine whether psychological player characteristics assessed by a self-administered questionnaire represent risk factors for injury. At baseline, female football players (14-16 years) were asked to complete a detailed questionnaire covering player history, previous injuries, perception of success and motivational climate, life stress, anxiety and coping strategies. During the 2005 season, a total of 1430 players were followed up to record injuries. A history of a previous injury [odds ratio (OR)=1.9 (1.4; 2.5), P<0.001] increased the risk of a new injury to the same region. There were significant differences in disfavor for previously injured compared with non-injured players for ego orientation (P=0.007), perception of a performance climate (P=0.003) and experienced stressful life events (P<0.001). However, only high life stress (P=0.001) and perception of a mastery climate (P=0.03) were significant risk factors for new injuries. In conclusion, a perceived mastery climate and a high level of life stress were significant predictors for new injuries in a cohort of young female football players.

Preventing injuries in female youth football--a cluster-randomized controlled trial

A set of exercises--the "11"--have been selected to prevent football injuries. The purpose of this cluster-randomized controlled trial was to investigate the effect of the "11" on injury risk in female youth football. Teams were randomized to an intervention (n=59 teams, 1091 players) or a control group (n=54 teams, 1001 players). The intervention group was taught the "11," exercises for core stability, lower extremity strength, neuromuscular control and agility, to be used as a 15-min warm-up program for football training over an 8-month season. A total of 396 players (20%) sustained 483 injuries. No difference was observed in the overall injury rate between the intervention (3.6 injuries/1000 h, confidence interval (CI) 3.2-4.1) and control group (3.7, CI 3.2-4.1; RR=1.0, CI 0.8-1.2; P=0.94) nor in the incidence for any type of injury. During the first 4 months of the season, the training program was used during 60% of the football training sessions, but only 14 out of 58 intervention teams completed more than 20 prevention training sessions. In conclusion, we observed no effect of the injury prevention program on the injury rate, most likely because the compliance with the program was low.

Performance aspects of an injury prevention program: a ten-week intervention in adolescent female football players

The injury rate in football is high, and effective injury prevention methods are needed. An exercise program, the "11," has been designed to prevent the most common injury types in football. However, the effect of such a program on performance is not known. The aim of this randomized-controlled trial was to investigate the effect of the "11" on performance after a 10-week training period. Thirty-four adolescent female football players were randomly assigned to either an intervention (n=18) or a control group (n=16). The "11" is a 15-min program consisting of ten exercises for core stability, lower extremity strength, balance and agility. Performance tests included isokinetic and isometric strength protocols for the quadriceps and hamstrings, isometric hip adduction and abduction strength, vertical jump tests, sprint running and soccer skill tests. There was no difference between the intervention and control groups in the change in performance from the pre- to post-test for any of the tests used. In conclusion, no effect was observed on a series of performance tests in a group of adolescent female football players using the "11" as a structured warm-up program.

Experiences with lithotripters: measurements of standardized fragmentation

A comparison of lithotripters in terms of the fragmentation efficacy was established by using artificial stones. Two hundred pulses were applied to identical calcium sulphate cubes at varied energy levels of different lithotripters. In the cubics the shock waves formed regular craters, which could be analyzed with regard to depth, diameter, and volume. Dimensions of the craters increased with increasing energy. Each shock wave source designed a typical crater form. Different efficacies of fragmentation within different lithotripters could be recognized. High focal peak pressures did not guarantee better fragmentation effects. By using different acoustic lenses in the same electromagnetic lithotripter, the influence of different focus zones of the shock wave on the fragmentation could be investigated without any changes of the energy input. Results clearly emphasize the possibility of an increase of fragmentation efficacy by changing only the focal zones and the distribution of energy within the focal area.

Butorphanol/diazepam compared to meperidine/diazepam for sedation in oral maxillofacial surgery: a double-blind evaluation

Butorphanol and meperidine, each combined with titrated diazepam, 10 to 20 mg, were compared in a randomized, double-blind trial for their sedative-analgesic effects. The fifty patients underwent multiple dental extractions under local anesthesia and sedation in an outpatient clinic. Butorphanol was significantly superior to meperidine with respect to the diazepam dose required to achieve the target level of sedation, the total diazepam dose administered, the clinical level of sedation, the surgeon's overall evaluations of effectiveness and of sedation level, and several patient evaluation parameters measured at discharge from the recovery room and at follow-up interview. All study drugs were well tolerated. Butorphanol offers clinical advantages over meperidine when combined with diazepam for sedation analgesia in outpatient oral surgery.