Current Sports-medicine News Results

Navigated intra-articular ACL reconstruction with additional extra-articular tenodesis using the same hamstring graft.

Knee Surg Sports Traumatol Arthrosc. 2010 Sep 1;
Colombet PD

PURPOSE: In some complex cases, standard anterior cruciate ligament reconstruction is not enough and could lead to a new failure. Lateral extra-articular reconstruction should be added. We describe a new mini-invasive technique using the same hamstring graft for intra-articular reconstruction and lateral tenodesis, optimized with navigation. METHOD: This arthroscopic technique is precisely described, different graft setting are possible, four strands graft inside the joint and two strands for the tenodesis or two strands graft for all the whole graft. As the lateral tenodesis is not anatomic, tunnel placement could be tricky. The use of navigation system is a real advantage for this technique with optimal tunnels placement. RESULTS: No results are given. CONCLUSION: This technique is comparable to others reported previously, showing a clinical advantage and no increasing of osteoarthritis. The use of the same graft avoids collateral damages, and navigation improves the graft placement.

Direct and long-term detection of gene doping in conventional blood samples.

Gene Ther. 2010 Sep 2;
Beiter T, Zimmermann M, Fragasso A, Hudemann J, Niess AM, Bitzer M, Lauer UM, Simon P

The misuse of somatic gene therapy for the purpose of enhancing athletic performance is perceived as a coming threat to the world of sports and categorized as 'gene doping'. This article describes a direct detection approach for gene doping that gives a clear yes-or-no answer based on the presence or absence of transgenic DNA in peripheral blood samples. By exploiting a priming strategy to specifically amplify intronless DNA sequences, we developed PCR protocols allowing the detection of very small amounts of transgenic DNA in genomic DNA samples to screen for six prime candidate genes. Our detection strategy was verified in a mouse model, giving positive signals from minute amounts (20 mul) of blood samples for up to 56 days following intramuscular adeno-associated virus-mediated gene transfer, one of the most likely candidate vector systems to be misused for gene doping. To make our detection strategy amenable for routine testing, we implemented a robust sample preparation and processing protocol that allows cost-efficient analysis of small human blood volumes (200 mul) with high specificity and reproducibility. The practicability and reliability of our detection strategy was validated by a screening approach including 327 blood samples taken from professional and recreational athletes under field conditions.Gene Therapy advance online publication, 2 September 2010; doi:10.1038/gt.2010.122.

Comparative effects of 6-week balance, gluteus medius strength, and combined programs on dynamic postural control.

J Sport Rehabil. 2010 Aug; 19(3): 268-87
Leavey VJ, Sandrey MA, Dahmer G

CONTEXT: There are few outcomes-based studies that address hip strategy and gluteus medius strength (GMS) for maintaining dynamic postural control. OBJECTIVE: To determine whether GMS training, proprioception training, or a combination of the 2 has an effect on dynamic postural control. DESIGN: Pretest-posttest, repeated measures. SETTING: Sports-medicine clinic. PARTICIPANTS: 48 healthy male and female college students obtained via sample of convenience. INTERVENTIONS: Three 6-wk programs including exercises for proprioception, GMS, and combined. MAIN OUTCOMES MEASURES: Eight Star Excursion Balance Test (SEBT) reach distances and GMS for the dominant leg. RESULTS: There was no significant difference between groups. The combination group demonstrated the most improvements in SEBT reach distances, whereas the GMS group demonstrated the most improvement in GMS. CONCLUSION: Use of exercises for proprioception, GMS, or a combination of the 2 will help improve dynamic postural control in healthy, active individuals.

Osseous Deficits After Anterior Cruciate Ligament Injury and Reconstruction: A Systematic Literature Review With Suggestions to Improve Osseous Homeostasis.

Arthroscopy. 2010 Sep; 26(9): 1248-1257
Nyland J, Fisher B, Brand E, Krupp R, Caborn DN

PURPOSE: This systematic review was performed to improve our understanding of the current evidence regarding the influence of anterior cruciate ligament (ACL) injury and reconstruction on involved lower extremity apparent bone mineral density, bone content, or bone area mass (bone integrity). METHODS: Two independent reviewers performed a Medline search from 1966 to January 2010 using the terms "anterior cruciate ligament" or "ACL" combined with "wound" or "injury" and "bone density" or "osteoporosis." Study inclusion criteria were English-language human studies. Reference sections of selected studies were also reviewed. RESULTS: Ten studies were identified that met our inclusion criteria. Eight studies performed ACL reconstruction with bone-patellar tendon-bone autografts and interference screw fixation. One study performed ACL reconstruction by use of Achilles tendon allografts with interference screw and staple fixation. Two ACL injury studies either did not involve ACL reconstruction or attempted primary repair with sutures. All studies reported varying levels of decreased bone mineral density, bone content, or bone area mass (bone integrity) at the involved lower extremity after ACL injury that did not return to premorbid levels even with ACL reconstruction and rehabilitation. Sites of reduced bone integrity included the proximal and distal femur, proximal tibia, patella, and calcaneus. Bone loss was increased with limited weight bearing and prolonged disuse or immobilization; however, significant improvements were not observed with accelerated rehabilitation. Some studies reported relations between Lysholm, Tegner, International Knee Documentation Committee survey, or function scores and bone integrity, whereas others reported no or poor relations. CONCLUSIONS: Involved lower extremity bone integrity is decreased after ACL injury. Current evidence suggests that premorbid bone integrity is not re-established after ACL reconstruction even when accelerated rehabilitation is performed. Recommendations to improve osseous homeostasis and bone health after ACL injury and reconstruction are provided.

Lower Extremity Compensatory Neuromuscular and Biomechanical Adaptations 2 to 11 Years After Anterior Cruciate Ligament Reconstruction.

Arthroscopy. 2010 Sep; 26(9): 1212-1225
Nyland J, Klein S, Caborn DN

PURPOSE: To determine whether compensatory neuromuscular and biomechanical adaptations exist after successful anterior cruciate ligament reconstruction and rehabilitation. METHODS: Seventy subjects, 5.3 +/- 3 years after surgery, participated in this study. Sagittal-plane lower extremity kinematic, gluteus maximus, vastus medialis, medial hamstring, and gastrocnemius electromyography (EMG) and vertical ground reaction force data were collected during single-leg countermovement jump (CMJ) performance. RESULTS: Women had lower propulsive and landing forces, lower CMJ heights, less hip and knee flexion, and greater angular hip, knee, and ankle velocities than men (P

Sport participation, sport injury, risk factors and sport safety practices in Calgary and area junior high schools.

Paediatr Child Health. 2009 Sep; 14(7): 439-44
Emery C, Tyreman H

OBJECTIVES: To examine rates of sport participation, sport injury, risk factors and sport safety practices in young adolescents. DESIGN: Cross-sectional. SETTING: Calgary and area junior high schools. PARTICIPANTS: A random sample of 1466 students (aged 12 to 15 years). OUTCOME MEASURES: Sport injury within one year prior to completing the survey. RESULTS: Ninety-three per cent of students participated in sports in the previous year. The injury rate was 60.85 injuries/100 students/year (95% CI 58.29 to 63.35) for students reporting at least one sport injury, 29.4 injuries/100 students/year (95% CI 27.08 to 31.81) for medically treated injuries, and 12.28 injuries/100 students/year (95% CI 10.64 to 14.07) for injuries presenting to a hospital emergency department. The greatest proportion of injuries occurred in basketball (14%), soccer (12%), hockey (8.6%) and snowboarding/skiing (7.1%). CONCLUSIONS: The rates of participation and injury in sports are high in junior high school students. Future research should focus on prevention strategies in sports with high participation and injury rates to have the greatest population health impact.

Mechanics of pole vaulting: a review.

Sports Biomech. 2010 Jun; 9(2): 123-38
Frère J, L'hermette M, Slawinski J, Tourny-Chollet C

A good understanding of the mechanics of pole vaulting is fundamental to performance because this event is quite complex, with several factors occurring in sequence and/or in parallel. These factors mainly concern the velocities of the vaulter-pole system, the kinetic and potential energy of the vaulter and the strain energy stored in the pole, the force and torque applied by the athlete, and the pole design. Although the pole vault literature is vast, encompassing several fields such as medicine, sports sciences, mechanics, mathematics, and physics, the studies agree that pole vault performance is basically influenced by the energy exchange between the vaulter and pole. Ideally, as the athlete clears the crossbar, the vaulter mechanical energy must be composed of high potential energy and low kinetic energy, guaranteeing the high vertical component of the vault. Moreover, the force and torque applied by the vaulter influences this energy exchange and these factors thus must be taken into consideration in the analysis of performance. This review presents the variables that influence pole vault performance during the run-up, take-off, pole support, and free flight phases.

Sport-Related Concussion in Children and Adolescents.

Pediatrics. 2010 Sep; 126(3): 597-615
Halstead ME, Walter KD,

Sport-related concussion is a "hot topic" in the media and in medicine. It is a common injury that is likely underreported by pediatric and adolescent athletes. Football has the highest incidence of concussion, but girls have higher concussion rates than boys do in similar sports. A clear understanding of the definition, signs, and symptoms of concussion is necessary to recognize it and rule out more severe intracranial injury. Concussion can cause symptoms that interfere with school, social and family relationships, and participation in sports. Recognition and education are paramount, because although proper equipment, sport technique, and adherence to rules of the sport may decrease the incidence or severity of concussions, nothing has been shown to prevent them. Appropriate management is essential for reducing the risk of long-term symptoms and complications. Cognitive and physical rest is the mainstay of management after diagnosis, and neuropsychological testing is a helpful tool in the management of concussion. Return to sport should be accomplished by using a progressive exercise program while evaluating for any return of signs or symptoms. This report serves as a basis for understanding the diagnosis and management of concussion in children and adolescent athletes.

Characteristic pattern of skeletal muscle remodelling in different mouse strains.

Int J Exp Pathol. 2010 Aug 27;
Lagrota-Candido J, Canella I, Pinheiro DF, Santos-Silva LP, Ferreira RS, Guimarães-Joca FJ, Lannes-Vieira J, Quirico-Santos T

Summary Muscular injury associated with local inflammatory reaction frequently occurs in sports medicine, but the individual response and capacity of regeneration vary among subjects. Inflammatory cytokines are probably implicated in activation of repair mechanisms by specifically influencing tissue microenvironment. This work aimed to compare muscle tissue repair in different mouse lineages. We used C57BL/6 and BALB/c mice genetically predisposed to either Type1 or Type2 cytokine production. The role of Type1 cytokines was also investigated in C57IFN-gamma (IFNgamma-KO) and C57IL-12 (IL12-KO) knockout mice. Participation of T lymphocytes was assessed in athymic BALB/c nude (nu/nu) mice. Muscular lesion was induced with bupivacaine injection in the Triceps brachii muscle. BALB/c mice showed marked collagen deposition and increased TGF-beta mRNA content, contrasting with mild fibrosis observed in C57BL/6 mice. C57-IFNgamma-KO mice, exhibited pronounced fibrosis, but IL12-KO collagen deposition was similar to that of C57. Twenty-four hours after lesion, C57BL/6 and BALB/c(nu/nu) presented numerous regenerating myofibres and marked increase of metalloprotease-9 activity compared with BALB/c. These data support that skeletal muscle remodelling is greatly influenced by the genetic backgrounds, shedding light on the molecular mechanisms influencing differential muscular remodelling and tissue regeneration among individuals.

Stress-induced multiple organ damage in rats is ameliorated by the antioxidant and anxiolytic effects of regular exercise.

Cell Biochem Funct. 2010 Aug; 28(6): 469-479
Cakır B, Kasımay O, Kolgazi M, Ersoy Y, Ercan F, Yeğen BC

Our aim was to investigate the effects of moderate load, regular swimming exercise on stress-induced anxiety, and associated oxidative organ injury. Male Sprague-Dawley rats (n = 48) were either kept sedentary or submitted to swimming exercise for 8 weeks. Rats were then divided as non-stressed, acute stress, and chronic stress groups. After acute or chronic stress (electric foot shocks) applications, rats were placed on a holeboard and the exploratory behavior was recorded to assess the anxiety. Rats were decapitated after the stress application. Acute and chronic stress induction led to increased serum cortisol levels as compared to non-stressed groups. Plasma aspartate aminotransferase levels that were elevated in sedentary rats with both stress exposures were lower in trained rats. Malondialdehyde levels and myeloperoxidase activity were increased in the cardiac muscle, liver, stomach, and brain of the stressed rats with a concomitant reduction in the glutathione levels, while stress-induced changes in malondialdehyde, myeloperoxidase, and glutathione levels were reversed in the trained animals. Exercise, which led to increased malondialdehyde and reduced glutathione levels in the skeletal muscle of the non-stressed rats, also protected against stress-induced oxidative damage. Regular exercise with its anxiolytic and antioxidant effects ameliorates stress-induced oxidative organ damage by a neutrophil-dependent mechanism. Copyright (c) 2010 John Wiley & Sons, Ltd.

Hormonal response to Taekwondo fighting simulation in elite adolescent athletes.

Eur J Appl Physiol. 2010 Aug 28;
Pilz-Burstein R, Ashkenazi Y, Yaakobovitz Y, Cohen Y, Zigel L, Nemet D, Shamash N, Eliakim A

Exercise training efficiency depends on the training load, as well as on the athlete's ability to tolerate it. The aim of the present study was to evaluate the effect of fighting simulation (3 fights, 6 min each, 30 min rest between fights) on anabolic (IGF-I, LH, FSH, estradiol, and testosterone) and catabolic hormones (cortisol) in elite, male (n = 10) and female (n = 10) adolescent (12-17 years) Taekwondo fighters. Blood samples were collected before the first and immediately after the third fight. The fighting simulation practice led to significant (p < 0.05) decreases in IGF-I (males -27.1 +/- 25.6, females -22.4 +/- 36.3 ng/ml), LH (males -0.7 +/- 1.2, females -2.3 +/- 3.3 U/L), and FSH (males -0.9 +/- 0.5, females -1.5 +/- 1.1 U/L), and to a significant increase (p < 0.05) in cortisol (males 141.9 +/- 30.1, females 64.1 +/- 30.6 mcg/dL) in both genders. Fighting simulation decreases in testosterone (males -1.9 +/- 1.6, females -0.02 +/- 0.06 ng/mL), and free androgen index (males -20.1 +/- 21.5, females -0.3 +/- 0.5) were significant (p < 0.05) only in male fighters. Exercise had no significant effect on estradiol, sex-hormone-binding globulins or thyroid function tests. Our data demonstrate that the physiologic and psychologic strain of a Taekwondo fighting simulation day led to a catabolic-type circulating hormonal response.

Effects of different resistance training intensity on indices of oxidative stress.

J Strength Cond Res. 2010 Sep; 24(9): 2491-7
Cakir-Atabek H, Demir S, Pinarbaşili RD, Gündüz N

Cakir-Atabek, H, Demir, S, Pinarbaşili, RD, and Gündüz, N. Effects of different resistance training intensity on indices of oxidative stress. J Strength Cond Res 24(9): 2491-2497, 2010-The purposes of this study were (a) to determine whether acute resistance exercise training (RET) induces oxidative stress, (b) to determine whether chronic RET decreases oxidative stress level at rest condition in previously untrained men, and (c) also to investigate how the RET intensity influences the training-induced oxidative stress response. Sixteen young men who did not have RET experience in the past were randomly divided in 2 groups. Hypertrophy-intensity group (n = 9) performed 3 sets of 12 repetitions at an intensity corresponding to 70% of 1 repetition maximum (1RM), whereas strength-intensity group (n = 7) performed 3 sets of 6 repetitions at an intensity corresponding to 85% of 1RM. Resistance exercise training involved 6 exercises, and it was performed 3 times a week on nonconsecutive days for 6 weeks. Blood samples were obtained just before (pre-RET) and immediately after RET (post-RET) on the first day of the first week, on the last day of the fourth and sixth weeks. The results indicated that malondialdehyde (MDA) significantly decreased (p < 0.05) in both groups immediately after RET; however, there was no significant acute alteration in glutathione (GSH) level in both groups (p > 0.05). After 6 weeks of training, pre-RET values of MDA significantly decreased and pre-RET values of GSH significantly increased in both hypertrophy- and strength-intensity groups (p < 0.05). These alterations occurred independently of training intensity. This study indicated that hypertrophy- and strength-intensity whole-body RET performed regularly for 6 weeks, decreased MDA concentration and increased GSH level in healthy young men. Results suggest that chronic RET has protective effects against oxidative stress similar to aerobic exercises and that these effects seem to be independent of the training intensity.

Activity profile and physiological requirements of junior elite basketball players in relation to aerobic-anaerobic fitness.

J Strength Cond Res. 2010 Sep; 24(9): 2330-42
Ben Abdelkrim N, Castagna C, Jabri I, Battikh T, El Fazaa S, Ati JE

Ben Abdelkrim, N, Castagna, C, Jabri, I, Battikh, T, El Fazaa, S, and El Ati, J. Activity profile and physiological requirements of junior elite basketball players in relation to aerobic-anaerobic fitness. J Strength Cond Res 24(9): 2330-2342, 2010-The aim of this research was to examine the demands of competitive basketball games and to study the relationship between athletes' physical capability and game performance. Physical and physiological game demands and the association of relevant field test with game performance were examined in 18 male junior basketball players. Computerized time-motion analysis, heart rate (HR), and blood-lactate concentration [BL] measurements were performed during 6 basketball games. Players were also measured for explosive power, speed, agility, and maximal-strength and endurance performance. During the games, players covered 7,558 +/- 575 m, of which 1,743 +/- 317; 1,619 +/- 280; and 2,477 +/- 339 m were performed at high, moderate, and low intensities, respectively. The 19.3 +/- 3.5 and 56.0 +/- 6.3% of the playing time was spent above 95% and at 85-95% of maximal HR, respectively. Average and mean peak [BL] were 5.75 +/- 1.25 and 6.22 +/- 1.34 mmol.L, respectively. Distances covered at maximal- and high-speed running significantly (p < 0.01) decreased during the second half. Game maximal- and high-speed running were significantly correlated with endurance performance (r = 0.52, p < 0.05 and r = 0.49, p < 0.05, respectively). High-intensity shuffling distance resulted in being negatively related with agility (r = -0.68, p < 0.05). This study showed that basketball players experience fatigue as game time progresses and suggests the potential benefit of aerobic and agility conditioning in junior basketball.

Analysis of the effects of androgens and training on myostatin propeptide and follistatin concentrations in blood and skeletal muscle using highly sensitive Immuno PCR.

Mol Cell Endocrinol. 2010 Aug 26;
Diel P, Schiffer T, Geisler S, Hertrampf T, Mosler S, Schulz S, Wintgens KF, Adler M

Myostatin propeptide (MYOPRO) and follistatin (FOLLI) are potent myostatin inhibitors. In this study we analysed effects of training and androgens on MYOPRO and FOLLI concentrations in blood and skeletal muscle using Immuno PCR. Young healthy males performed either a 3-month endurance-training or a strength-training. Blood and biopsy samples were analysed. Training did not significantly affect MYOPRO and FOLLI concentrations in serum and muscle. To investigate whether total skeletal muscle mass may affect circulating MYOPRO and FOLLI levels, blood samples of tetraplegic patients, untrained volunteers and bodybuilders were analysed. MYOPRO was significantly increased exclusively in the bodybuilder group. In orchiectomized rats MYOPRO increased in blood and muscle after treatment with testosterone. In summary our data demonstrate that moderate training does not affect the concentrations of MYOPRO to FOLLI. In contrast androgen treatment results in a significant increase of MYOPRO in skeletal muscle and serum.

Predicting dynamic knee joint load with clinical measures in people with medial knee osteoarthritis.

Knee. 2010 Aug 26;
Hunt MA, Bennell KL

Knee joint loading, as measured by the knee adduction moment (KAM), has been implicated in the pathogenesis of knee osteoarthritis (OA). Given that the KAM can only currently be accurately measured in the laboratory setting with sophisticated and expensive equipment, its utility in the clinical setting is limited. This study aimed to determine the ability of a combination of four clinical measures to predict KAM values. Three-dimensional motion analysis was used to calculate the peak KAM at a self-selected walking speed in 47 consecutive individuals with medial compartment knee OA and varus malalignment. Clinical predictors included: body mass; tibial angle measured using an inclinometer; walking speed; and visually observed trunk lean toward the affected limb during the stance phase of walking. Multiple linear regression was performed to predict KAM magnitudes using the four clinical measures. A regression model including body mass (41% explained variance), tibial angle (17% explained variance), and walking speed (9% explained variance) explained a total of 67% of variance in the peak KAM. Our study demonstrates that a set of measures easily obtained in the clinical setting (body mass, tibial alignment, and walking speed) can help predict the KAM in people with medial knee OA. Identifying those patients who are more likely to experience high medial knee loads could assist clinicians in deciding whether load-modifying interventions may be appropriate for patients, whilst repeated assessment of joint load could provide a mechanism to monitor disease progression or success of treatment.

Anatomic Outcome of Percutaneous Release Among Patients With Trigger Finger.

J Hand Surg Am. 2010 Aug 26;
Calleja H, Tanchuling A, Alagar D, Tapia C, Macalalad A

PURPOSE: To investigate the adequacy and safety of percutaneous trigger finger release on symptomatic patients. METHODS: Two orthopedic non-hand surgeons performed percutaneous A1 pulley release on the thumb, index, middle, and ring fingers with the use of a 19-gauge needle in 25 fingers of 24 patients. Open inspection was then performed to determine the extent of release and any injury to the surrounding anatomic structures. RESULTS: Triggering was eliminated in all fingers. Of the 25 A1 pulleys, 19 were partially released; only 6 were completely released. Noted injury included only superficial abrasions in 15 tendons. None of the patients had injury to the digital artery or nerve. CONCLUSIONS: In the percutaneous release of trigger fingers, complete anatomic release of the A1 pulley is not always adequately achieved, even though clinically patients experience relief of triggering. It is a safe procedure for the thumb, index, middle, and ring fingers as long as the recommended technique is observed.

Injury Patterns in Female Irish Dancers.

PM R. 2010 Aug 25;
Noon M, Hoch AZ, McNamara L, Schimke J

OBJECTIVE: To determine the type of Irish dance injuries requiring evaluation and treatment by a sports medicine physician. DESIGN: Cross-sectional retrospective chart review. SETTING: Academic sports medicine center in the Midwest. PARTICIPANTS: Female Irish dancers who presented at an academic sports medicine center from June 2002 to September 2009. MAIN OUTCOME MEASURES: This was a retrospective chart review identifying injuries sustained to female Irish dancers in a single Irish dance company in a major metropolitan area. Dancers were evaluated and injuries were diagnosed by one sports medicine physician at an academic sports medicine center. RESULTS: Sixty-nine female Irish dancers, ages 8 to 23 years, sustained 217 recorded injuries. The top injuries included stress fractures (29.9%), patellofemoral pain syndrome (11.1%), Sever condition (6.0%), ankle sprains (5.1%), posterior tibialis tendonitis (4.6%), and plantar fasciitis (4.6%). The most common site for stress fractures were the sesamoids, comprising 27.7% of all stress fractures and 8.3% of total injuries. The majority of injuries were in the lower extremities (94.9%), remaining injuries involved the lumbosacral spine and pelvis (5.1%). Most dancers (79.7%) had multiple injuries. The number of injuries per dancer increased as the dancer's level increased. There was a trend for the average age of the dancers to decrease as the level of skill increased. CONCLUSION: Lower extremity injuries comprised the majority of Irish dance injuries. Stress fractures (29.9%), patellofemoral pain syndrome (11.1%), and Sever condition (6.0%) were the most common injuries.

Effect of Q-angle on patellar positioning and thickness of knee articular cartilages.

Surg Radiol Anat. 2010 Aug 27;
Tsakoniti AE, Mandalidis DG, Athanasopoulos SI, Stoupis CA

The purpose of the present study was to investigate whether an increased quadriceps angle (Q-angle) has an effect on patellar positioning and/or the thickness of the medial and lateral tibiofemoral and patellofemoral articular cartilage and menisci, in a group of young asymptomatic individuals. These individuals were detected in a previous study with a decreased anatomical cross-sectional area of the vastus medialis and lateralis as a result of an increased Q-angle. Patellar positioning and the thickness of the articular cartilages were determined in 19 asymptomatic male individuals with high Q-angle (HQ-angle) (18.5 degrees +/- 2.6 degrees ) using magnetic resonance imaging (MRI). Seventeen male counterparts with low Q-angle (10.1 degrees +/- 1.9 degrees ) were used for comparison. The position of the patella was determined by measuring the sulcus angle, the lateral patella tilt, the patella-lateral condyle index and the bisect offset (BSO) with the quadriceps relaxed. The BSO, was also measured with the quadriceps under maximum isometric voluntary contraction. The thickness of the articular cartilages of the lateral and medial femoral condyles, the tibial condyles, the patellar facets and the menisci were also measured. Our data revealed that healthy individuals with HQ-angle are unlikely to demonstrate any changes in the position of the patella and/or the thickness of the knee articular cartilages. The decreased anatomical area of the vastus medialis and an almost equally atrophied vastus lateralis, which was previously observed in this group of individuals may prevent in part the misalignment of the patella and early wear of the tibiofemoral and patellofemoral articular cartilages.

THE COL5A1 GENE: A NOVEL MARKER OF ENDURANCE RUNNING PERFORMANCE.

Med Sci Sports Exerc. 2010 Aug 23;
Posthumus M, Schwellnus MP, Collins M

BACKGROUND:: Running economy, a key component of endurance ability, has been shown to be associated with flexibility. Increased stiffness (inflexibility) may improve running economy and therefore endurance running ability. The COL5A1 gene, which encodes the alpha1-chain of type V collagen was found to associate with measures of flexibility. Type V collagen is a quantitatively minor fibrillar collagen, which is believed to regulate fibrillogenesis within tendons and other connective tissue. METHODS:: Running economy, a key component of endurance ability, has been shown to be associated with flexibility. Increased stiffness (inflexibility) may improve running economy and therefore endurance running ability. The COL5A1 gene, which encodes the ?1-chain of type V collagen was found to associate with measures of flexibility. Type V collagen is a quantitatively minor fibrillar collagen, which is believed to regulate fibrillogenesis within tendons and other connective tissue. PURPOSE:: The aim of this study was therefore to determine if the COL5A1 gene is associated with endurance performance. METHODS:: 313 Caucasian male participants who completed either the 2006 or the 2007 226km South African Ironman triathlon (3.8km swim, 180km bike, 42.2km run) participated in this study. All participants were genotyped for the COL5A1 BstUI restriction fragment length polymorphism (RFLP). RESULTS:: The COL5A1 BstUI RFLP was significantly associated with time to complete the running component of the triathlon. Participants with a TT genotype completed the running component of the race significantly faster than individuals with a CC genotype (P=0.019; TT = 294.2 +/- 52.1 minutes; CC, 307.4 +/- 48.6 minutes). In addition, there was a significant linear trend (P=0.020) in the CC genotype distribution when the run times were divided into the fastest (CC=13%), middle (17%) and slowest (25%) tertiles. There were no significant genotype differences for time to complete the swim, the bike, or the overall race. The COL5A1 BstUI RFLP, BMI, age and 15 week running training history predicted 30% of the variance in running performance. CONCLUSION:: This is the first study to identify the COL5A1 BstUI RFLP as a marker for endurance running performance. Further studies are required to replicate these findings.

Influence of Knowledge of Sprint Number on Pacing During Repeated-Sprint Exercise.

Med Sci Sports Exerc. 2010 Aug 23;
Billaut F, Bishop DJ, Schaerz S, Noakes TD

PURPOSE:: The anticipation of exercise-induced stress influences performance during continuous exercise. However, not all exercise is continuous. This study explores the influence of prior knowledge of sprint number on mechanical work, surface electromyogram (EMG), and rating of perceived exertion (RPE) during repeated-sprint exercise (RSE). METHODS:: Fourteen athletes performed three RSE in random order. In one trial, subjects were informed that they would perform ten, 6-s cycle sprints (with 24 s of rest) and then completed ten sprints (control trial, CL). In a second trial, subjects were told to perform five sprints, but after the fifth sprint, they were asked to perform an additional five sprints (deception trial, DC). In a third trial, subjects were not told how many sprints they would be performing, but were stopped after 10 sprints (unknown trial, UN). Data were recorded for every sprint. RESULTS:: Both the initial-sprint work and work accumulated over the first five sprints were greater (6.5%, P < 0.05) in the DC than in the CL and UN trials. Furthermore, the work accumulated over the ten sprints was lower (4.0%, P < 0.05) in the UN trial than in the two other trials. The EMG was greater (P < 0.05) in the DC than in the CL and UN trials during the initial sprint (8.8%) and over the first five sprints (9.1%). The sprint-induced decrease in EMG and work occurred earlier in the UN trial compared with the CL and DC trials. The RPE profile was similar in all trials. CONCLUSIONS:: Results demonstrate that pacing occurs during short repeated-sprint efforts in anticipation of the number of sprints that are included in the trial.