Mid Sweden University

Background

Physical activities during leisure time as well as school hours have changed over the past few years, with adolescents being less physically active and adopting a sedentary lifestyle.

Objective

The overall objective of this mixed-methods study was to evaluate the feasibility of introducing a 4-min Tabata interval training into a lower secondary school context. A further aim was to evaluate the possible effects on: coordination, balance, and strength.

Methods

The study was conducted as an intervention study with a mixed-method approach. Forty-three children, aged 7–9 years, participated in the intervention group. Additionally, 13 children were recruited as a control group. The intervention itself was delivered by the teachers and was performed for 4-min every day in a classroom setting. All participants performed physical tests before and after the intervention period to evaluate the Tabata training. After the completion of the 6-week Tabata interval training, the four teachers were interviewed.

Results

The push-ups (p = 0.004), kneeling push-ups (p = 0.03), and standing long jump (p = 0.01) improved in the intervention group after 6 weeks. No differences were observed between the genders. The teachers experienced that it worked well to integrate the Tabata interval training in the classroom setting.

Conclusion

After 6 weeks, a school-based Tabata intervention program improved physical performance. The teachers saw no obstacles in including the Tabata intervention program in a classroom setting and pointed out several positive aspects such as an increased energy level and development in the children’s movement patterns.

PURPOSE: The aim was to study possible differences of muscle injuries regarding type, localization and the extent of injury between the dominant and non-dominant leg in elite male football players. Another aim was to study the injury incidence of muscle injuries of the lower extremity during match and training.

METHODS: Data were consecutively collected between 2007 and 2013 in a prospective cohort study based on 54 football players from one team of the Swedish first league. The injury incidence was calculated for both match and training, injuries to the hip adductors, quadriceps, hamstrings and triceps surae were diagnosed and evaluated with ultrasonography, and their length, depth and width were measured to determine the extent of structural muscle injuries.

RESULTS: Fifty-four players suffered totally 105 of the studied muscle injuries. Out of these 105 injuries, the dominant leg was affected in 53 % (n = 56) of the cases. A significantly greater extent of the injury was found in the dominant leg when compared with the non-dominant leg with regard to structural injuries of the hamstrings. No other significant differences were found.

CONCLUSIONS: Structural hamstring muscle injuries were found to be of greater extent in the dominant leg when compared with the non-dominant leg. This new finding should be taken into consideration when allowing the football player to return to play after leg muscle injuries.

LEVEL OF EVIDENCE: IV.

In sports, there is a constant discussion about the hyper-pronation and supination of the foot during loading and its relation to injuries or dis-comfort. The purpose of the present study was to investigate the possi-ble differences in the subtalar joint in the midstance phase of running, between individuals with Pes Planus and Pes Cavus, after 5 min and 45 min of running. Thirty-four subjects, meeting the requirements for Pes Planus (30 feet) and Pes Cavus (35 feet), according to the criteria for Medial Longitudinal Arch-angle, were included in the study. The calca-neal vertical angle, representing the eversion/inversion of the subtalar joint, was measured using with two-dimensional digital analysis and Dartfish Software with the subjects running barefoot on a treadmill, be-fore and after 45 min of outside running wearing shoes. Both individuals with Pes Cavus and Pes Planus showed a significant increase in the calcaneal eversion (P < 0.05) after 45 min of running. Between the groups, there was a significantly greater eversion of the Pes Planus, on the right foot, after 45 min of running (P < 0.05) compared to the Pes Ca-vus. The effect of fatigue evident in the present study suggests that fur-ther biomechanical research should be considered when exposing the foot to the repetitive nature of running, conditions most likely responsi-ble for the overrepresented overuse injuries among runners. 

The purpose was to examine the test-retest reliability of the Rolimeter measurement procedure in the acute time phase, following a substantial knee trauma. In total, 15 participants with acute knee trauma were examined by one single observer at three different time-points with the Rolimeter using a maximum force. The selected time-points were: baseline (0–7 days after the trauma), midpoint (3–4 weeks after the trauma), and endpoint (3–4 weeks after the trauma). The anterior-posterior displacement was recorded where the endpoint evaluation was used as the reference value. The mean anterior laxity scores remained constant over the measurement time-points for both knees, with an anterior laxity that was 2.7 mm higher (on average) in the injured than the noninjured knee (9.5 mm vs. 6.8 mm). The mean difference (i.e., bias) between laxity scores, for the injured knee, measured at endpoint versus baseline was 0.2±1.0 mm and −0.2±1.1 mm when measured at endpoint versus midpoint, with average typical errors of 0.7 and 0.8 mm and intra-class correlations that were very strong (both r=~0.93). For the same comparisons on the noninjured knee, systematic bias was close to zero (0.1±0.3 and −0.1±0.3 mm, respectively), and both the intra-class correlations were almost perfect (r=~0.99). The current study implicates that repeated Rolimeter measurements are relatively reliable for quantifying anterior knee laxity during the acute time-phases following knee trauma. Hence, the Rolimeter, in combination with manual tests, seems to be a valuable tool for identifying anterior cruciate ligament injuries.

Objectives: The heel-rise test is used to assess the strength and endurance of the plantar flexors in everyday clinical practice. However, several factors may affect outcomes, including sex, age, body mass index and activity level. The aims of this study were to revisit the reliability and normative values of this test, and establish normative equations accounting for several factors. Design: Cross-sectional observational study with test-retest. Setting: Community. Participants: Volunteers (n = 566, age 20 to 81 years). Interventions: Subjects performed single-legged heel rises to fatigue, standing on a 10° incline, once on each leg. A subset of subjects (n = 32) repeated the test 1 week later. Reliability was quantified using intraclass (ICC) correlation coefficients and Bland-Altman plots (mean difference [95% limits of agreement (LOA)]), whereas the impact of sex, age, body mass index and activity level on the number of heel rises was determined using non-parametric regression models. Results: The test showed excellent reliability (ICC = 1.0 right leg, 1.0 left leg), with mean between-day differences in the total number of heel-rise repetitions of 0.2 (95% LOA -6.2 to 6.5) and 0.1 (95% LOA -6.1 to 6.2) for right and left legs, respectively. Overall, males completed more repetitions than females (median 24 vs 21). However, older females (age >60. years) outperformed older males. According to the model, younger males with higher activity levels can complete the most heel rises. Conclusions: The heel-rise test is highly reliable. The regression models herein can be employed by clinicians to evaluate the outcomes of heel-rise tests of individuals against a comparable normative population.

The aim of this study was to evaluate the symmetry of anthropometry and muscle function in cross-country skiers and their association to vertical jumping power. Twenty cross-country skiers were recruited (21.7 ± 3.8 yrs, 180.6 ± 7.6 cm, 73.2 ± 7.6 kg). Anthropometric data was obtained using an iDXA scan. VO2max was determined using the diagonal stride technique on a ski treadmill. Bilateral functional tests for the upper and lower body were the handgrip and standing heel-rise tests. Vertical jump height and power were assessed with a counter movement jump. Percent asymmetry was calculated using a symmetry index and four absolute symmetry index levels. At a group level the upper body was more asymmetrical with regard to lean muscle mass (p = 0.022, d = 0.17) and functional strength (p = 0.019, d = 0.51) than the lower body. At an individual level the expected frequencies for absolute symmetry level indexes showed the largest deviation from zero for the heel-rise test (χ2 = 16.97, p = 0.001), while the leg lean mass deviated the least (χ2 = 0.42, p = 0.517). No relationships were observed between absolute symmetry level indexes of the lower body and counter movement jump performance (p > 0.05). As a group the skiers display a more asymmetrical upper body than lower body regarding muscle mass and strength. Interestingly at the individual level, despite symmetrical lean leg muscle mass the heel-rise test showed the largest asymmetry. This finding indicates a mismatch in muscle function for the lower body.

Soccer is the biggest sport in the world, resulting in a large number of injuries occurring in this game.Many soccer players today are ready physically, but not mentally, to return to play. The aim of thisstudy was to investigate injured players’ perception of their time after a sports injury has occurred. Thestudy was conducted using a qualitative approach. Eight soccer players, four male and four female,aged 14–25 years, were interviewed individually. The material was analysed using manifest content ana-lysis. The participants reported on various psychological aspects that affected them both positively andnegatively during the rehabilitation period. Individual factors included the injured players’ reaction,motivation and fear. Situational factors, such as their coach, the team, their family and the physiother-apist, also influenced the participants. In conclusion, several psychological factors affect young soccerplayers’ perception of rehabilitation after a severe injury. This study found that support from the teamand the coach is often lacking in a soccer player’s rehabilitation.

This study investigated the injury profile among elite male youth soccer players in a Swedish first league during two seasons. The present cohort study is based on data collected during the 2013-2014 seasons. In total, 43 young elite male soccer players, aged 15 to 19 yr, were prospectively followed regarding injuries, time of exposure, injury location, type of injury, and injury severity. The overall incidence of injury in the present study was estimated to 6.8 injuries per 1,000 exposure hours and 15.5 and 5.6 injuries per 1,000 hr for matches and training, respectively. The single most common injury subtype was muscle strain (53%). The hip and groin were the most common locations for injuries. Thirty-one percent of the injuries were classified as severe injury and caused >28 days absence from training and match play. Both the injury incidence and the number of serious injury seems to be relatively high in youth elite players according to this study. Although the injury incidence seems to be slightly lower than in adult elite players the injuries seem to be more traumatic in youth elite players.

PURPOSE: The aim of this study was to make a comparison between players in two age groups in an elite male soccer team regarding injury localisation within the muscle-tendon unit, injury size and muscle group in terms of muscle injuries of the lower extremity. METHODS: Cohort study based on data collected from a Swedish elite male soccer team during the seasons 2007-2012. In total, 145 muscle injuries were included. Injury localisation to the tendon or muscle, the size of haematoma and the affected muscle group were assessed using ultrasound. Age comparison was made between younger players (</=23 years) and older players (>23 years). RESULTS: No difference regarding injury localisation to either the tendon or the muscle, or the size of haematoma between the two age groups was found. However, the older group of players suffered a significantly higher number of injuries to the triceps surae than the younger players (p = 0.012). CONCLUSIONS: In a Swedish team of male soccer players at elite level, there was no difference between players 23 years or younger and players older than 23 years, in terms of injury distribution to muscles or tendons. Players older than 23 years sustained more injuries to triceps surae when compared with players 23 years or younger. The clinical relevance is to pay attention to muscle function of triceps surae in older players and to screen those players who may need an injury prevention programme. LEVEL OF EVIDENCE: II.