Karim Chamari and Roald Bahr
Simone Ciacci, Rocco Di Michele, Silvia Fantozzi and Franco Merni
Kinematic asymmetry is believed to be associated with elevated risk for muscle injury, but little is known about the links between hamstring injuries and asymmetry of sprinting mechanics.
To evaluate the value of kinematic analysis of sprinting for the detection of injury-related asymmetry in athletes with a history of hamstring strain.
Six sub-elite male sprinters, including two who sustained a hamstring strain injury.
Absolute differences between left and right symmetry indices and symmetry angles were both calculated for ground contact time and selected angular displacements. Measurements were acquired at foot strike, during the stance phase, and at toe-off.
At toe-off, injured athletes exhibited greater knee flexion and less hip extension for the injured extremity compared to the uninjured extremity. Symmetry indices for these variables markedly exceeded an established 15% threshold for clinically relevant asymmetry. Each of the uninjured athletes exhibited a high degree of symmetry for all parameters, with mean values for symmetry indices significantly lower than the 15% threshold (P < 0.05).
Kinematic analysis of sprinting asymmetry appears to be valuable for identification of elevated risk for hamstring injury.
Damien McKay, Carolyn Broderick and Katharine Steinbeck
With the advent of long-term athlete development programs and early sport specialization, the training of elite athletes now spans the period of adolescence. Adolescence represents a period of physical, psychosocial and cognitive development, but also a time of physical and psychological vulnerability. Changes in skeletal and physiological attributes coincide with an increased risk of sport related injury. A window of vulnerability is shaped by the properties of the musculoskeletal system, the influence of pubertal hormones and the lag time between physical and cognitive development. This article aims to challenge the assumption of adolescence as a time of increased vigor alone, by highlighting the presence of specific vulnerabilities, and proposing that the hormonal, musculoskeletal, and neurocognitive changes of adolescence may represent intrinsic risk factors for sport related injury.
Alison R. Snyder, Tamara Valovich McLeod and Anna J. Hartman
Column-editor : Michael G. Dolan
Alex T. Strauss, Austin J. Parr, Daniel J. Desmond, Ashmel T. Vargas and Russell T. Baker
, injuries per 1000 athlete exposures have been found to occur at a rate between 2.51 and 4.36. 3 , 4 Analysis of injury patterns indicates repetitive overuse as the more common causes of injury. 1 Thus, identification of sport injury risk factors has become a focus across multiple disciplines in health
Marco Hagen, Ewald M. Hennig and Peter Stieldorf
Nordic walking (NW) was compared with walking (W) and running (R) with respect to upper and lower limb injury risks. 24 NW-instructors performed W, NW, and R trials on a runway covered with artificial turf at controlled speeds. Foot pronation and ground reaction forces were measured as well as shock wave transmission to the right wrist. Comparison of NW and W shows similar results for all of the four chosen velocities (5 km/h, 7 km/h, 8 km/h, 8.5 km/h). Except for the 2nd peak of the vertical ground reaction force, NW results in higher loading rates and horizontal forces as well as higher pronation and pronation velocity values as compared with W. Wrist acceleration values up to 7.6 times gravitational acceleration were recorded in NW. Compared with R at the same speeds (8 km/h and 8.5 km/h), NW can be recommended as low impact sport with 36% lower loading rates and 59% lower pronation velocities. However, the high wrist accelerations in NW reveal that the upper extremities are exposed to considerable repetitive shocks, which may cause overuse injuries of the upper extremities. Thus, additional preventive exercises for the upper limb muscles are recommended as well as using shock absorbing walking poles.
Ted A. Kaplan and Mary Helen Campbell
Little information is available on the safety of supervised exercise programs for children. This retrospective case review describes the experience over 5 years in a private, outpatient, physician-directed therapeutic exercise program. Observations were made on a total of 47 patients referred by their physicians or parents for exercise programs for diseases, including obesity (26), cystic fibrosis (10), cardiac disease (3), asthma (3), and others (5). Patients performed circuit training with an exposure that consisted of 2,646 total sessions (56.3 ± 63.3 sessions/patient), equivalent to 1,507.9 hours (32.1 ± 35.5 hr/patient) of exercise time. There were three minor accidents (1.9/1,000 patient hours). Physical examination by the attending physician was negative in all three cases: No treatment was indicated, and no patient missed any training time due to these incidents. No significant injuries or cardiorespiratory complications were observed in this exercise program.
Marta Stepien-Slodkowska, Krzysztof Ficek, Pawel Zietek, Mariusz Kaczmarczyk, Wioletta Lubkowska, Miroslawa Szark-Eckardt and Pawel Cieszczyk
The most commonly injured body part for skiing has been found to be the knee. The rupture of the anterior cruciate ligament (ACL) was the most frequent diagnosis. ACL ruptures are determined by several extrinsic and intrinsic risk factors including those that are hormonal, neuromuscular, anatomical, or genetic.
To examine the association of both COL1A1 rs1800012 (+1245G/T) and COL1A1 rs1107946 (–1997G/T) polymorphisms, individually and as haplotypes, with ACL ruptures in recreational Polish skiers.
Genomic DNA was extracted from buccal cells donated by the subjects, and genotyping was carried out using real-time polymerase chain reaction.
138 male recreational skiers with surgically diagnosed primary ruptures and 183 apparently healthy male recreational skiers not differing markedly in age or level of exposure to ACL injury.
Main Outcome Measures:
COL1A1 rs1800012 and COL1A1 rs1107946 polymorphisms.
There were significant differences in genotype distribution of the COL1A1 rs1800012 polymorphism between the ACL rupture group and the control group. The GG homozygotes were underrepresented in the ACL rupture group compared with the control group. There were no significant differences in genotype distribution or allele frequency of COL1A1 rs1107946 polymorphisms between the ACL rupture group and the control group. The G-G (COL1A1 rs1800012G and COL1A1 rs1107946G) haplotype was the most common. There were no significant differences in haplotype distribution between the ACL-rupture and control groups.
The study showed that GG homozygotes were underrepresented in the ACL-rupture group compared with the control group, which suggests an association with reduced risk of ACL injury.