Musculoskeletal ultrasound imaging of proximal and distal hamstrings cross sectional area in individuals with history of anterior cruciate ligament reconstruction.

BACKGROUND: Ultrasound (US) imaging is used by physical therapists for diagnosis and assessment of musculoskeletal injury and follow-up. PURPOSE: The aim was to identify long-term effects of graft harvesting on hamstrings muscle mass among athletes who had undergone anterior cruciate ligament reconstruction (ACLR). METHODS: Twenty-eight participants (ages 18-55) were recruited: 18 with history of ACLR using semitendinosus (ST) autograft and 10 healthy controls. Images of the cross-sectional area (CSA) of ST and biceps femoris (BF) were captured at 30% and 70% of the distance from the ischial tuberosity to the popliteal crease. A mixed model ANOVA was used to identify inter-limb differences in the CSA of ST and BF at each location, for each group. RESULTS: Inter-limb differences were found for the CSA of ST but not BF across both locations for the ACLR group, not controls (p < .001). Within the ACLR group, ST atrophy of the injured limb was relatively greater at the distal vs. proximal location (p < .001). CONCLUSION: US imaging identified selective atrophy of ST on the injured side with no compensatory hypertrophy of BF. Specific rehabilitation may influence muscle mass of medial vs. lateral hamstrings muscle groups after ACLR using a ST graft, and monitored with US imaging.

[Physique of children and adolescents in Northern Iceland then and now].

INTRODUCTION: In the first half of the 20th century, Icelandic doctors and teachers began documenting the health of school children, believing that physical measurements were important to monitoring physical development. The measurements could also be used for comparison in other areas and for reasearch. At the Reginonal Archives of Skagafjordur, rare data about the physique of children in Saudarkrokur in 1912-1953, measured by Jon Th. Bjornsson, is preserved. MATERIAL AND METHODS: Height, weight, grip strenght, thorax expansion and tidal volume were measured twice in 2018-2019 on 7-15-year-old children in elementary schools in Saudarkrokur and Varmahlid. These measurements were compared with similar measurements from 1912-1953. RESULTS: Children in 2018-2019 at ages 7-15 years were significantly taller, heavier, with greater thorax expansion and tidal volume than their peers in 1912-1953 (p<0,001-0,037). Children in 2018-2019 at ages 7-14 years had significantly higher body mass index than their peers in 1912-1953 (p<0,001-0,027). If adjusted for height and weight in thorax expansion and tidal volume measurements, similar results were found. Children in 2018-2019 had significantly less grip strength than their peers in 1912-1953 at ages 7 and 9-12-years when adjusted for height and weight (p<0,001-0,025). There was significant development in the physique of children over the years 1912-1953 in most measurements and age groups (p<0,001-0,040). CONCLUSIONS: A significant increase in measured factors in 2018-2019 compared to 1912-1953 can possibly be attributed to improved quality of life.

Injury Pattern in Icelandic Elite Male Handball Players.

OBJECTIVE: To examine the incidence, type, location, and severity of injuries in Icelandic elite male handball players and compare across factors like physical characteristics and playing position. DESIGN: Prospective cohort study. SETTING: The latter part of the preseason and the competitive season of Icelandic male handball. PARTICIPANTS: Eleven handball teams (185 players) from the 2 highest divisions in Iceland participated in the study. Six teams (109 players) completed the study. VARIABLES MEASURED: Injuries were recorded by the players under supervision from their team physiotherapists or coaches. Coaches recorded training exposure, and match exposure was obtained from the Icelandic and European Handball Federations. The players directly recorded potential risk factors, such as age, height, weight, previous injuries, and player position. MAIN OUTCOME MEASURES: Injury incidence and injury location and number of injury days. RESULTS: Recorded time-loss injuries were 86, of which 53 (62%) were acute and 33 (38%) were due to overuse. The incidence of acute injuries was 15.0 injuries/1000 hours during games and 1.1 injuries/1000 hours during training sessions. No significant difference was found in injury incidence between teams, but number of injury days did differ between teams (P = 0.0006). Acute injuries were most common in knees (26%), ankles (19%), and feet/toes (17%), but overuse injuries occurred in low back/pelvic region (39%), shoulders (21%), and knees (21%). Previous knee injuries were the only potential risk factor found for knee injury. CONCLUSIONS: The results indicate a higher rate of overuse injuries in low back/pelvic region and shoulders than in comparable studies.

Using Pressure Massage for Achilles Tendinopathy: A Single-Blind, Randomized Controlled Trial Comparing a Novel Treatment Versus an Eccentric Exercise Protocol.

BACKGROUND: Eccentric exercises are the only conservative treatment that has shown good clinical results in studies of Achilles tendinopathy (AT), but success rates vary, indicating the need for alternative treatments. Soft tissue treatments are widely used for AT, but strong scientific evidence is lacking to support those treatments. PURPOSE/HYPOTHESES: This study aimed to determine whether pressure massage to the calf muscles is a useful treatment for AT and to compare this treatment versus an eccentric exercise protocol. Our first hypothesis was that pressure massage treatment is equivalent or superior to eccentric exercises with regard to pain reduction time (ie, pain would be reduced more quickly with pressure massage). The second hypothesis was that pressure massage is equivalent or superior to eccentric exercises with regard to function of the calf muscles. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 60 patients with AT were randomized into 3 groups: group 1 underwent an eccentric exercise protocol, group 2 underwent pressure massage, and group 3 underwent pressure massage and the eccentric exercise protocol. Patients were evaluated with the Icelandic version of the Victorian Institute of Sports Assessment-Achilles questionnaire (VISA-A-IS), an algometer to test the pressure pain threshold (PPT) of the Achilles tendon, tests for ankle range of motion (ROM), and real-time ultrasonographic (US) scanning of tendon thickness and degree of neovascularization. Measurements for VISA-A-IS, PPT, and ROM were taken at 0, 4, 8, 12, and 24 weeks. US scan measurements were taken at 0, 12, and 24 weeks. Mixed-model analysis of variance was used for statistical analysis. RESULTS: All groups improved when evaluated with VISA-A-IS scores (P < .0001). The pressure massage group improved significantly more than the eccentric exercise group at week 4, which was the only between-group difference. Ankle ROM increased significantly over time (ROM bent knee P = .006 and ROM straight knee P = .034), but no significant difference was found between groups. No significant difference was found in evaluations of PPT or US scan measurements. CONCLUSION: Pressure massage is a useful treatment for Achilles tendinopathy. Compared with eccentric exercise treatment, pressure massage gives similar results. Combining the treatments did not improve the outcome.

Effects of an Education and Prevention Course for University Music Students on Their Body Awareness and Attitude Toward Health and Prevention.

BACKGROUND: Studies show a high cumulative prevalence of musculoskeletal disorders among musicians. Increased emphasis is needed on studying the effectiveness of education and prevention courses in music schools. OBJECTIVES: To investigate the effects on music students of an education and prevention course on body awareness and their attitude toward health and prevention. METHODS: 23 music students participated in this prospective descriptive comparative study, with 13 students taking the course and serving as a prevention education group (PG) and 10 students serving as a comparison group (CG). The course met once weekly for 2 semesters and included lectures and practical sessions. Before and after the course, participants answered a questionnaire about their level of physical activity, warm-up exercises prior to musical performance, health-promoting activities, and subjective body awareness during musical performance and during activities of daily living (ADL). RESULTS: Over the 9-month study period, the PG group increased, and the CG lessened, the amount of warm-up prior to music performance, showing a significant group difference after the course (p=0.036). Significant interactions were seen for subjective body awareness scores (between groups over time) during practice (p=0.026) and during ADLs (p=0.004), as the PG group had greater positive change over time. No group differences were found in students' subjective rating of body awareness during live performance. CONCLUSIONS: Participation in a prevention and education course may be beneficial for music students due to improved subjective body awareness and attitude toward prevention strategies.

Effects of Sex and Fatigue on Biomechanical Measures During the Drop-Jump Task in Children.

BACKGROUND: Female athletes have a higher rate of anterior cruciate ligament (ACL) injury than males from adolescence and into maturity, which is suggested to result from sex-specific changes in dynamic movement patterns with maturation. Few studies have studied movement strategies and response to fatigue in children. PURPOSE: To evaluate the effect of fatigue on biomechanical variables associated with increased risk for ACL injury during a drop-jump (DJ) performance in children. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 116 children (mean age, 10.4 years) were recruited from local sports clubs and performed 5 repetitions of a DJ task before and after a fatigue protocol. Kinematic and kinetic data from initial contact (IC) to the first peak vertical ground reaction force (vGRF) were analyzed for both limbs, including limb and fatigue as within-subject factors for analyses between boys and girls. Pearson correlation coefficients were calculated to identify associations between variables of interest. RESULTS: Girls demonstrated greater peak vGRF values than boys (by 8.1%; P < .05), there were greater peak vGRF values for the right limb than the left (by 6.2%; P < .001), and fatigue led to slightly greater values (P < .05). Although weak, the correlation between peak vGRF values and knee flexion excursion was stronger for girls (r = -0.20) than boys (r = -0.08) (P < .006). Fatigue resulted in greater knee flexion angles at IC and less excursion during landing, more so for girls (by 6.1° vs 1.4°; interaction, P < .001), although the knee flexion moment was generally lowered by fatigue (P < .001). Limb asymmetry in knee flexion moments was more pronounced for boys than for girls (interaction, P < .05), contrary to that seen in frontal plane knee moments, where asymmetry was much greater in girls than boys (interaction, P < .001). CONCLUSION: Even as young athletes, girls and boys seem to adopt dissimilar movement strategies and are differently affected by fatigue. CLINICAL RELEVANCE: Injury prevention programs should be considered at an earlier age in an effort to lower the risk of ACL injury in athletes.

Playing-related musculoskeletal disorders among icelandic music students: differences between students playing classical vs rhythmic music.

Most research studies investigating the prevalence of musculoskeletal disorders affecting musicians and music students have focused on classical music, while less is known about their prevalence in other music genres. The purpose of this study was to document cumulative and point prevalence of playing-related musculoskeletal disorders (PRMD) among music students in Iceland and, specifically, to identify differences between those studying classical vs rhythmic music. We hypothesized that students of classical music would report more frequent and more severe musculoskeletal disorders than students involved in rhythmic music, as classical instruments and composition typically require more demanding, sustained postures during practice and performance. A total of 74 students from two classical music schools (schools A and B) and 1 rhythmic school (school C) participated in the study by answering a questionnaire assessing PRMDs. The results showed that 62% of participants had, at some point in their musical career, suffered a PRMD. The cumulative prevalence was highest in music school A (71.4%) and lowest in music school C (38.9%). A statistically significant difference was identified between the cumulative prevalence of PRMD from schools A and B combined compared to music school C (p=0.019). Over 40% of participants reported a "current PRMD," and a significant difference was identified between the three schools (p=0.011), with the highest point prevalence being registered in music school A (66.6%) and the lowest in music school C (22.2%). The prevalence of PRMDs among Icelandic music students was high. The difference found between students who play classical vs rhythmic music may be explained by different demands of the instruments and composition on playing posture.

Estimating Size and Trend of the North Interlake Woodland Caribou Population Using Fecal-DNA and Capture-Recapture Models.

A critical step in recovery efforts for endangered and threatened species is the monitoring of population demographic parameters. As part of these efforts, we evaluated the use of fecal-DNA based capture-recapture methods to estimate population sizes and population rate of change for the North Interlake woodland caribou herd (Rangifer tarandus caribou), Manitoba, Canada. This herd is part of the boreal population of woodland caribou, listed as threatened under the federal Species at Risk Act (2003) and the provincial Manitoba Endangered Species Act (2006). Between 2004 and 2009 (9 surveys), we collected 1,080 fecal samples and identified 180 unique genotypes (102 females and 78 males). We used a robust design survey plan with 2 surveys in most years and analysed the data with Program MARK to estimate encounter rates (p), apparent survival rates (ϕ), rates of population change (λ), and population sizes (N). We estimated these demographic parameters for males and females and for 2 genetic clusters within the North Interlake. The population size estimates were larger for the Lower than the Upper North Interlake area and the proportion of males was lower in the Lower (33%) than the Upper North Interlake (49%). Population rate of change for the entire North Interlake area (2005-2009) using the robust design Pradel model was significantly <1.0 (λ = 0.90, 95% CI: 0.82-0.99) and varied between sex and area with the highest being for males in Lower North Interlake (λ = 0.98, 95% CI: 0.83-1.13) and the lowest being for females in Upper North Interlake (λ = 0.83, 95% CI: 0.69-0.97). The additivity of λ between sex and area is supported on the log scale and translates into males having a λ that is 0.09 greater than females and independent of sex, Lower North Interlake having a λ that is 0.06 greater than Upper North Interlake. Population estimates paralleled these declining trends, which correspond to trends observed in other fragmented populations of woodland caribou along the southern part of their range. The results of this study clearly demonstrate the applicability and success of non-invasive genetic sampling in monitoring populations of woodland caribou. © 2012 The Wildlife Society.

Pelvic floor muscle function before and after first childbirth.

INTRODUCTION AND HYPOTHESIS: Pregnancy and vaginal delivery are considered to be the main risk factors for development of pelvic floor dysfunction. We hypothesize that; 1) pelvic floor muscle (PFM) strength and endurance is significantly reduced by first delivery in general, and 2) changes in PFM strength and endurance are influenced by mode of delivery. METHODS: Prospective repeated measures observational study. Thirty-six women completed the study. PFM function was measured as vaginal squeeze pressure. Paired t-test was used to compare PFM function before and after first childbirth for all participants as a group. One-way ANOVA was used to compare changes between different modes of delivery. RESULTS: A significant reduction in PFM strength (p < 0.0001) and endurance (p < 0.0001) was found for all participants after first childbirth. The reduction in strength was 20.1 hPa (CI:16.2; 24.1), 31.4 hPa (CI: 7.4; 55.2) 5.2 hPa (CI: -6.6; 17.0) in the normal vaginal, instrumental vaginal and acute cesarean groups, respectively. The difference was significant between normal vaginal and acute cesarean birth (p = 0.028) and instrumental vaginal and acute cesarean birth (p = 0.003). CONCLUSION: PFM strength is significantly reduced after vaginal delivery, both normal and instrumental, 6 to 12 weeks postpartum. Acute cesarean section resulted in significantly less muscle strength reduction.

Test-retest intra-rater reliability of vaginal measurement of pelvic floor muscle strength using Myomed 932.

OBJECTIVES: To investigate test-retest intra-rater reliability of measurements of pelvic floor muscle (PFM) strength using Myomed 932 (Enraf-Nonius, Delft, the Netherlands). DESIGN: Test-retest intra-rater reliability test with a 2-7 day interval. SETTING: Physiotherapy outpatient clinic in association with the Department of Physiotherapy, University of Iceland. POPULATION: Twenty healthy female volunteers in Reykjavik metropolitan area, Iceland, with a mean age of 43.8 (SD 9.8) years, mean body mass index (BMI) 26.2 (SD 5.3), and mean parity 2.1 children (SD 1.0). MAIN OUTCOME MEASURES: PFM strength during two attempts of maximal voluntary contraction (MVC) measured as vaginal squeeze pressure in hectoPascals (hPa). RESULTS: Mean MVC was 34.45 hPa (95% CI: 26.07-42.83) on Day 1 and 34.05 hPa (95% CI: 26.66-41.44) on Day 2. The measurements ranged from 5-74 hPa interindividually on Day 1 and 5-62 hPa on Day 2. Intraclass Correlation Coefficient (ICC) was 0.97; p < 0.001 and coefficient of variation (CV%) was 11.09%. There was no significant difference between the first and second tests (p = 0.74). CONCLUSION: This test-retest intra-rater reliability study for Myomed 932 showed a very good reliability using ICC. The CV%, however, indicated some degree of intra-individual variation. We suggest that this device can be used both in practice and clinical trials for assessing female PFM strength.

No effect of a video-based awareness program on the rate of soccer injuries.

BACKGROUND: The injury rate in soccer is high, and effective injury prevention methods are needed. PURPOSE: To test the effect of a video-based awareness program on the incidence of acute injuries in soccer. STUDY DESIGN: Randomized control trial; Level of evidence, 1. METHODS: Participants were elite male soccer players from the top 2 divisions in Iceland. Fifteen of 20 teams completed the study: 7 intervention teams (127 players) and 8 control teams (144 players) chosen by random. Just before the start of the 2000 soccer season, the intervention teams were visited with an intervention program. The program included a 15-minute presentation with information on the injury risk of playing elite soccer, typical injuries, and their mechanisms. Then the players worked together in pairs and analyzed video sequences to develop preventive strategies. The 12 video sequences were selected from the previous Icelandic soccer season, representing 3 typical injury mechanisms that accounted for more than half of all incidents recorded. During the season, team physical therapists prospectively recorded all acute injuries, and coaches recorded training exposure on a special form. Injury incidence was compared between groups and between the 1999 and 2000 seasons for teams that participated in both seasons. RESULTS: No difference was observed in injury incidence between the intervention (6.6 +/- 0.7 injuries per 1000 player hours) and control groups (6.6 +/- 0.7 injuries per 1000 player hours). Furthermore, there was no difference in injury location or type. CONCLUSION: The video-based injury awareness program showed no effect on injury rate.

A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players.

PURPOSE: To compare the effects of a 10-week training program with two different exercises -- traditional hamstring curl (HC) and Nordic hamstrings (NH), a partner exercise focusing the eccentric phase -- on muscle strength among male soccer players. METHODS: Subjects were 21 well-trained players who were randomized to NH training (n = 11) or HC training (n = 10). The programs were similar, with a gradual increase in the number of repetitions from two sets of six reps to three sets of eight to 12 reps over 4 weeks, and then increasing load during the final 6 weeks of training. Strength was measured as maximal torque on a Cybex dynamometer before and after the training period. RESULTS: In the NH group, there was an 11% increase in eccentric hamstring torque measured at 60 degrees s(-1), as well as a 7% increase in isometric hamstring strength at 90 degrees, 60 degrees and 30 degrees of knee flexion. Since there was no effect on concentric quadriceps strength, there was a significant increase in the hamstrings:quadriceps ratio from 0.89 +/- 0.12 to 0.98 +/- 0.17 (11%) in the NH group. No changes were observed in the HC group. CONCLUSION: NH training for 10 weeks more effectively develops maximal eccentric hamstring strength in well-trained soccer players than a comparable program based on traditional HC.

A prospective video-based analysis of injury situations in elite male football: football incident analysis.

BACKGROUND: The mechanisms for football injuries are largely unknown. AIM: To describe the characteristics of injury situations in elite male football using a video-based method called football incident analysis. STUDY DESIGN: Prospective cohort study. METHODS: During the 1999 season, videotapes from 52 matches in the Icelandic elite football league were reviewed. Incidents (N = 95) were recorded when the match was interrupted by the referee because of a suspected injury. Team physical therapists recorded injuries prospectively (N = 28 time-loss injuries). RESULTS: Duels caused 84 of the incidents, mostly tackling duels (n = 54). The exposed player's attention appeared to be focused away from the opponent in 93% of the cases. The 3 main mechanisms observed were (1) breakdown attacks, tackling from the side or the front, attention focused on the ball (24%); (2) defensive tackling duels, attention focused on the ball or low ball control (20%); and (3) heading duels, attention focused on the ball in the air (13%). CONCLUSION: Most incidents and injuries occurred during breakdown attacks and when a player was involved in tackling duels. Player attention appeared to be focused mainly on the ball, not on the opponent challenging him to gain ball possession.

Video analysis of the mechanisms for ankle injuries in football.

BACKGROUND: Although ankle sprains are frequent in football, little is known about their mechanisms. PURPOSE: To describe the injury mechanisms for ankle injuries in male elite football. STUDY DESIGN: Prospective cohort study. METHODS: Videotapes and injury information were collected for 313 of 409 matches from Norwegian and Icelandic elite football during the 1999 to 2000 seasons. Video recordings of incidents that resulted in ankle injuries were analyzed and cross-referenced with injury reports from the team medical staff. RESULTS: A total 46 acute ankle injuries were reported to have occurred, that is, 4.5 injuries per 1000 match hours. Of these, 26 (57%) were identified on the videotapes. Two mechanisms thought to be specific to football were found: 1) player-to-player contact with impact by an opponent on the medial aspect of the leg just before or at foot strike, resulting in a laterally directed force causing the player to land with the ankle in a vulnerable, inverted position; and 2) forced plantar flexion where the injured player hit the opponent's foot when attempting to shoot or clear the ball. CONCLUSIONS: Systematic video analysis provides detailed information on the mechanisms for ankle injuries in football-for lateral ligament sprains and for the condition dubbed "footballer's ankle."

Risk factors for injuries in football.

BACKGROUND: The injury risk in football is high, but little is known about causes of injury. PURPOSE: To identify risk factors for football injuries using a multivariate model. STUDY DESIGN: Prospective cohort study. METHODS: Participants were 306 male football players from the two highest divisions in Iceland. Before the 1999 football season started, the following factors were examined: height, weight, body composition, flexibility, leg extension power, jump height, peak O(2) uptake, joint stability, and history of previous injury. Injuries and player exposure were recorded throughout the competitive season. RESULTS: Older players were at higher risk of injury in general (odds ratio [OR] = 1.1 per year, P = 0.05). For hamstring strains, the significant risk factors were age (OR = 1.4 [1 year], P < 0.001) and previous hamstring strains (OR = 11.6, P <0.001). For groin strains, the predictor risk factors were previous groin strains (OR = 7.3, P = 0.001) and decreased range of motion in hip abduction (OR = 0.9 [1 degrees ], P = 0.05). Previous injury was also identified as a risk factor for knee (OR = 4.6) and ankle sprains (OR = 5.3). CONCLUSIONS: Age and previous injury were identified as the main risk factors for injury among elite football players from Iceland.

Physical fitness, injuries, and team performance in soccer.

PURPOSE: To investigate the relationship between physical fitness and team success in soccer, and to test for differences in physical fitness between different player positions. METHODS: Participants were 306 male soccer players from 17 teams in the two highest divisions in Iceland. Just before the start of the 1999 soccer season, the following variables were tested: height and weight, body composition, flexibility, leg extension power, jump height, and peak O2 uptake. Injuries and player participation in matches and training were recorded through the 4-month competitive season. Team average physical fitness was compared with team success (final league standing) using a linear regression model. Physical fitness was also compared between players in different playing positions. RESULTS: A significant relationship was found between team average jump height (countermovement jump and standing jump) and team success (P = 0.009 and P = 0.012, respectively). The same trend was also found for leg extension power (P = 0.097), body composition (% body fat, P = 0.07), and the total number of injury days per team (P = 0.09). Goalkeepers demonstrated different fitness characteristics from outfield players. They were taller and heavier, more flexible in hip extension and knee flexion, and had higher leg extension power and a lower peak O2 uptake. However, only minor differences were observed between defenders, midfield players, and attackers. CONCLUSION: Coaches and medical support teams should pay more attention to jump and power training, as well as preventive measures and adequate rehabilitation of previous injuries to increase team success.