Flexibility

Maturation, morphological, motor and technical characteristics of under 16 female track and field athletes

Abstract There is growing interest in identifying morphological, motor, maturation characteristics, as well as their changes, of children and adolescents in systematized training in various sports. Knowledge of these characteristics is important for coaches and researchers because they provide parameters for assessing youth development during training. For track and field, studies on the category under 16 are scarce. Thus, the objectives of this study are to describe the profile and to design a percentile table of morphological, motor, maturation and event-specific variables of under 16 athletes. 105 young athletes were evaluated on two consecutive days. On the first day, an anamnesis of athletes and coaches was performed. Anthropometric and anaerobic measurements were analyzed in shot put, long jump, 800 m run. On the second day, flexibility, vertical impulse, upper limb strength, speed and maximal aerobic speed were evaluated. The biological maturation was evaluated by the percentage of the predicted height. A table with percentiles was prepared with the data of all athletes. Another table with the results of the whole group plus mean and standard deviation was prepared. A last table was prepared containing data divided by group of sports events. The morphological variables presented differences between the groups as to body mass, BMI and sum of skinfolds. Significant differences were observed only for the motor variable VMA. No significant differences were observed only for long jump. When divided by groups, it was evident that throwers are different from the other athletes in some morphologic variables and in specific sports events.

The COL5A1 genotype is associated with range of motion

PURPOSE

The aim of our study was to investigate the association between COL5A1 genotype and Range of Motion as measured by the passive straight leg raise (SLR) and whole body join laxity (WBJL) in Asian population.

METHODS

One hundred and seventy seven participants including Korean and Japanese college students (male = 109, female = 68) participated in the study. Each subject performed the passive straight leg raise and whole body join laxity test. Genotyping for the COL5A1 (rs 12722) polymorphism was performed using the TaqMan approach. The COL5A1 genotype exhibited a Hardy-Weinberg equilibrium distribution in our population.

RESULTS

The physical parameters including height, weight, and BMI were higher in < 90° group than > 90° group. The SLR exhibited significant difference among the COL5A1 group. However, the WBJL did not differ significantly among the COL5A1 genotype, but significant difference was seen in CC genotype when compared to CT (2.99 ± 1.72) or TT (2.70 ± 1.52) genotype.

CONCLUSION

We concluded that COL5A1 gene polymorphism is associated with increased SLR ROM in Asian population.

The injured runner

Running is often recommended by physicians to maintain a healthy lifestyle. As more individuals participate in running-related activities, clinicians must be increasingly aware of common injuries. Training errors leading to overuse are the most common underlying factors in most running-related injuries. Clinicians need to keep in mind that the presenting injury is frequently the result of an inability to compensate for a primary dysfunction at another site. Although imaging may be helpful in differentiating among diagnoses with similar clinical presentations, a detailed history and physical examination are essential in making a correct diagnosis.

Age-related mobility loss is joint-specific: an analysis from 6,000 Flexitest results

Although aging is commonly linked to a reduction in joint range of motion, it is unclear if all body joints behave similarly. To address this issue, the main purpose of this study was to compare age-related loss of mobility of seven body joints. A total of 6,000 participants (3,835 men and 2,165 women) aged 5 to 92 years took part in this study. The maximal passive range of motion of 20 movements was evaluated by Flexitest, and each movement was scored from 0 to 4. Composite scores were obtained for each of seven joints and for overall flexibility (Flexindex (FLX)) by adding individual movement scores. Confirming previous findings, FLX systematically decreased with aging (p < .001), with female participants being more flexible for all ages (p < 0.001) and having a more gradual, 0.6% vs. 0.8%/year, age reduction (p < .001). Starting at 30 and 40 years, respectively, for male and female participants, the relative contribution of each composite joint score to FLX dramatically changed. Shoulder contribution to FLX male's score went from 13.9% at 28 years of age to only 5.2% at 85 years of age. In general, proportionally, shoulder and trunk became less flexible, while elbow and knee mobility was preserved to a greater extent. Our findings indicated that age-related loss of mobility is rather joint-specific, which could be related to distinct routine usage patterns of the major body joints along life.

No association between COL3A1, COL6A1 or COL12A1 gene variants and range of motion

Approximately 64-70% of the variability in joint range of motion (ROM) is heritable. A common variant within a type V collagen (COL5A1) gene is associated with joint range of motion. Like type V collagen, types III, VI and XII collagen are also involved in fibril assembly and/or diameter regulation. Mutations within the genes that encode these proteins, COL3A1, COL6A1 and COL12A1, also cause connective tissue hypermobility disorders and phenotypes. The aim of this study was to determine if variants within these genes are associated with measures of joint range of motion. Three hundred and fifty apparently healthy and physically active Caucasian participants were recruited. Anthropometric measurements were taken. Sit-and-reach (SR), straight leg raise (SLR) and total shoulder rotation (ShTR) range of motion were measured. All participants were genotyped for COL3A1 rs1800255, COL6A1 rs35796750 and COL12A1 rs970547. COL3A1 rs1800255, COL6A1 rs35796750 and COL12A1 rs970547 were not significantly associated with sit-and-reach, straight leg raise or total shoulder rotation range of motion. Furthermore, no significant age-genotype interaction effects were identified between the variants and range of motion measurements. None of the variants investigated in this study were significantly associated with any of the measures of range of motion used. Further studies are required to identify additional intrinsic and extrinsic factors that may determine range of motion, including the genetic component.

Physical fitness of South African primary school children, 6 to 13 years of age: discovery vitality health of the nation study

Basic physical fitness was measured using 8 different measures for 10,295 South African children and youths (5,611 boys, 4,684 girls) ages 6 to 13 years. These measurements included height, weight, Body Mass Index, standing long jump, shuttle run, sit-and-reach, sit-up (EUROFIT testing battery), and cricket ball throw scores. Due to the effects of earlier apartheid laws on separating communities, it was hypothesized that scores for different ethnic groups may differ. Therefore, in addition to the calculation of basic norms and sex differences, ethnic differences were also tested. Height and weight, relative to age, were different between the various ethnic groups (Black, White, and Mixed ancestry) for boys, with Black boys being shorter and lighter than White boys. There were no differences in sit-and-reach flexibility scores between the groups. With the exception of the cricket ball throw for girls, White children had higher scores in most tests. Although not significantly different from the White children, in the majority of cases, the children of mixed ancestral origin had scores that ranged between the other two ethnic groups. These results suggest a need for encouraging fitness in school children, and the reintroduction of formal physical education into the South African school curriculum, especially into schools in which Black children predominate.

The COL5A1 Gene, Ultra-Marathon Running Performance, and Range of Motion

Purpose:

Endurance running performance is a multifactorial phenotype that is strongly associated with running economy. Sit and reach range of motion (SR ROM) is negatively associated with running economy, suggesting that reduced SR ROM is advantageous for endurance running performance. The COL5A1 gene has been associated with both endurance running performance and SR ROM in separate cohorts. The aim of this study was to investigate whether COL5A1 is associated with ultra-marathon running performance and whether this relationship could be partly explained by prerace SR ROM.

Methods:

Seventy-two runners (52 male, 20 female) were recruited from the 56 km Two Oceans ultra-marathon and were assessed for prerace SR ROM. The cohort was genotyped for the COL5A1 BsfUI restriction fragment length polymorphism, and race times were collected after the event.

Results:

Participants with a TT genotype (341 ± 41 min, N = 21) completed the 56 km Two Oceans ultra-marathon significantly (P = 0.014) faster than participants with TC and CC genotypes (365 ± 39 min, N = 50). The COL5A1 genotype and age accounted for 19% of performance variance. When the cohort was divided into performance and flexibility quadrants, the T allele was significantly (P = 0.044) over-represented within the fast and inflexible quadrant.

Conclusion:

The COL5A1 genotype was found to be significantly associated with performance in a 56 km ultra-endurance run. This study confirms previous findings and it furthers our understanding of the relationships among ROM, COL5A1, and endurance running performance. We continue to speculate that the COL5A1 gene alters muscle-tendon stiffness.

The COL5A1 gene: a novel marker of endurance running performance

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 α1-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 whether the COL5A1 gene is associated with endurance performance.

METHODS

Three hundred thirteen Caucasian male participants who completed either the 2006 or the 2007 226-km South African Ironman triathlon (3.8-km swim, 180-km bike, and 42.2-km 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; mean ± SD: TT = 294.2 ± 52.1 min, CC = 307.4 ± 48.6 min). 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 (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. COL5A1 BstUI RFLP, body mass index, age, and 15 wk of 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.

Flexibility for runners

Flexibility training, commonly referred to as stretching, has become a standard part of athletic training for nearly all sports. Athletes almost universally engage in some form of flexibility training because of the perception that it prevents injury and may enhance sports performance. With specific regard to running, controversy has arisen regarding these proposed benefits of stretching. In this article, the authors seek to define flexibility training and evaluate the evidence for its clinical benefit. They also describe the components of a general lower quarter flexibility program that they encourage their patients to follow at the University of Virginia Runner's Clinic.

Prevention of physical training-related injuries recommendations for the military and other active populations based on expedited systematic reviews

BACKGROUND

The Military Training Task Force of the Defense Safety Oversight Council chartered a Joint Services Physical Training Injury Prevention Working Group to: (1) establish the evidence base for making recommendations to prevent injuries; (2) prioritize the recommendations for prevention programs and policies; and (3) substantiate the need for further research and evaluation on interventions and programs likely to reduce physical training-related injuries.

EVIDENCE ACQUISITION

A work group was formed to identify, evaluate, and assess the level of scientific evidence for various physical training-related injury prevention strategies through an expedited systematic review process. Of 40 physical training-related injury prevention strategies identified, education, leader support, and surveillance were determined to be essential elements of a successful injury prevention program and not independent interventions. As a result of the expedited systematic reviews, one more essential element (research) was added for a total of four. Six strategies were not reviewed. The remaining 31 interventions were categorized into three levels representing the strength of recommendation: (1) recommended; (2) not recommended; and (3) insufficient evidence to recommend or not recommend.

EVIDENCE SYNTHESIS

Education, leadership support, injury surveillance, and research were determined to be critical components of any successful injury prevention program. Six interventions (i.e., prevent overtraining, agility-like training, mouthguards, semirigid ankle braces, nutrient replacement, and synthetic socks) had strong enough evidence to become working group recommendations for implementation in the military services. Two interventions (i.e., back braces and pre-exercise administration of anti-inflammatory medication) were not recommended due to evidence of ineffectiveness or harm, 23 lacked sufficient scientific evidence to support recommendations for all military services at this time, and six were not evaluated.

CONCLUSIONS

Six interventions should be implemented in all four military services immediately to reduce physical training-related injuries. Two strategies should be discouraged by all leaders at all levels. Of particular note, 23 popular physical training-related injury prevention strategies need further scientific investigation, review, and group consensus before they can be recommended to the military services or similar civilian populations. The expedited systematic process of evaluating interventions enabled the working group to build consensus around those injury prevention strategies that had enough scientific evidence to support a recommendation.

Bilateral and recurrent myositis ossificans in an athlete: a case report and review of treatment options

An unusual case of recurrent myositis ossificans (MO) bilaterally in the hamstring muscles of a 47-year-old athlete secondary to trauma is presented with a review of the literature of current treatment options. MO is a common condition that occurs among athletes in association with muscle and/or tendon strain or contusion. After an extensive literature review, we believe this to be the first case reported of recurrent and bilateral MO in a nonsurgical setting from recurrent hamstring strains. Plain radiographs and physical examination revealed the appearance and chronology of this pathology. Treatment options to improve flexibility and decrease morbidity are discussed along with prophylaxis for future injury. Treatment of mobility and flexibility, rehabilitation goals and treatment with nonsteroidal anti-inflammatory drugs, bisphosphonates, and magnesium are discussed along with prophylaxis.

Body composition and physical fitness of undernourished South African rural primary school children

OBJECTIVE

The purpose of this study was to determine the relationships between the body composition characteristics, body mass index (BMI), sum of skinfolds (SSF), % body fat (%BF), fat-free mass (FFM) and waist-to-hip ratio (WHR), and nine physical fitness items in undernourished rural primary school children in Ellisras, South Africa.

DESIGN

A cross-sectional study.

SETTING

The study consisted of 462 boys and 393 girls who were aged 7-14 y.

MEASUREMENTS

Five body composition measures were assessed: BMI, SSF, %BF, FFM and WHR. Nine physical fitness test items were assessed: standing long jump, bent arm hang, sit-ups, 10 x 5 m shuttle run, 50 m sprint, 1600 m run, flamingo balance, sit and reach, plate tapping.

RESULTS

BMI was highly correlated with FFM (r = 0.7, P < 0.001). In line with findings from Western countries, regression coefficients (B) showed that children with higher BMI or SSF performed worse in bent arm hang (girls, B = -0.84, P < 0.001, and B = -0.06, P = 0.02, respectively) and in 1600m run (B = 6.68, P < 0.001). BMI was significantly associated with flamingo balance (B = 0.26, P = 0.04). WHR was positively associated with bent arm hang (B = 9.37, P = 0.03), and inversely with sit and reach (B = -7.48, P = 0.01). In contrast, significant relationships were found between BMI and standing long jump (B = 0.74, P = 0.04), sit and reach (B = 0.51, P < 0.001), flamingo balance (B = 0.26, P = 0.04) and plate tapping (B = -19, P = 0.01). SSF was significantly associated with sit and reach (B = 0.04, P = 0.03). Significant inverse associations were found between FFM and bent arm hang (girls, B = -0.06, P = 0.05), 1600 m run (girls, B = -2.33, P = 0.003) and 50 m run (boys, B = -0.11, P = 0.006). FFM was significantly associated with standing long jump (boys, B = 0.99, P < 0.001; girls, B = 0.73, P < 0.001), flamingo balance (B = 0.17, P < 0.001), and with sit and reach (boys, B = 0.59, P = 0.03).

CONCLUSION

In the present study in undernourished children, body composition was significantly related to physical fitness, but not always in the expected direction. It is therefore important to note that in this population, BMI should not be interpreted as a measure of fatness/overweight, but rather as an indicator of muscle mass.

The impact of stretching on sports injury risk: a systematic review of the literature

PURPOSE

We conducted a systematic review to assess the evidence for the effectiveness of stretching as a tool to prevent injuries in sports and to make recommendations for research and prevention.

METHODS

Without language limitations, we searched electronic data bases, including MEDLINE (1966-2002), Current Contents (1997-2002), Biomedical Collection (1993-1999), the Cochrane Library, and SPORTDiscus, and then identified citations from papers retrieved and contacted experts in the field. Meta-analysis was limited to randomized trials or cohort studies for interventions that included stretching. Studies were excluded that lacked controls, in which stretching could not be assessed independently, or where studies did not include subjects in sporting or fitness activities. All articles were screened initially by one author. Six of 361 identified articles compared stretching with other methods to prevent injury. Data were abstracted by one author and then reviewed independently by three others. Data quality was assessed independently by three authors using a previously standardized instrument, and reviewers met to reconcile substantive differences in interpretation. We calculated weighted pooled odds ratios based on an intention-to-treat analysis as well as subgroup analyses by quality score and study design.

RESULTS

Stretching was not significantly associated with a reduction in total injuries (OR = 0.93, CI 0.78-1.11) and similar findings were seen in the subgroup analyses.

CONCLUSION

There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes. Further research, especially well-conducted randomized controlled trials, is urgently needed to determine the proper role of stretching in sports.

Active knee joint flexibility and sports activity

The aim of the study was to estimate active knee flexion and active knee extension in athletes and to investigate the potential association of each to different types of sports activity. Active knee extension and active knee flexion was measured in 339 athletes. Active knee extension was significantly higher in women than in men and significantly positively associated with weekly hours of swimming and weekly hours of competitive gymnastics. Active knee flexion was significantly positively associated with participation in basketball, and significantly negatively associated with age and weekly hours of soccer, European team handball and swimming. The results point to sport-specific adaptation of active knee flexion and active knee extension.

Lower extremity injuries in college athletes: relation between ligamentous laxity and lower extremity muscle tightness

OBJECTIVE

Two components of flexibility, muscle tightness, and ligamentous laxity in college athletes were studied to determine whether these factors were associated with the incidence of lower extremity injuries.

DESIGN

Prospective cohort study.

SETTING

College athletic department.

PARTICIPANTS

201 college athletes.

OUTCOME MEASURES

College men and women athletes were tested for ligamentous laxity with the Beighton scale and for muscle tightness with a new scale based on the tightness of the iliopsoas, iliotibial band, hamstring, rectus femoris, and gastrocsoleus muscles. Lower extremity injuries incurred during practice and play were recorded during the following year.

RESULTS

Of the 201 athletes tested, 71 sustained 115 injuries. For each additional point on the 9-point ligamentous laxity scale (9 = hyperlax), the risk of injury decreased 16%. For each additional point on the 10-point muscle-tightness scale (10 = all muscles tight), the risk of injury increased 23%. The two scores were moderately inversely correlated (Spearman's rho = -0.3; p < .001). Women had greater mean (+/- SD) laxity scores than men (3.3 +/- 2.2 vs. 1.8 +/- 2.0; p < .001) and lower mean overall muscle tightness scores (1.5 +/- 1.6 vs. 3.5 +/- 2.1; p < .001). Among Women athletes, the rate of lower extremity injury was unrelated to ligamentous laxity or to flexibility. Among men, lower extremity injuries were associated with lower ligamentous laxity scores (p = .008) and greater muscle tightness (p = .04).

CONCLUSIONS

This study introduces a new scale for lower extremity muscle tightness. Tight ligaments and muscles are related to injury in men, but not women, college athletes. A preseason flexibility program may decrease injuries in college men athletes.

Lower extremity muscular flexibility in long distance runners

Muscle tightness is often considered to be a predisposing factor in muscle injuries. The purpose of this study was to assess the muscle flexibility of the hamstrings, rectus femoris, iliopsoas, gastrocnemius, and soleus muscles in long distance runners. Range of motion measurements of five movements, including hip flexion with knee extended, hip extension with knee flexed, hip extension with knee extended, ankle dorsiflexion with knee extended, and ankle dorsiflexion with knee flexed, were evaluated to determine muscle tightness. Twenty runners and 20 nonrunners volunteered for the study. Each group consisted of 10 males and 10 females. The observed means were compared between runners and nonrunners, males and females, plus the dominant and nondominant leg using a three-way analysis of variance. The runners were found to have tighter hamstrings (p < .05), and soleus (p < .05) muscles than nonrunners. There was no significant difference in rectus femoris and iliopsoas muscle tightness in runners compared with nonrunners. In addition, the males had tighter hamstring muscles than the females in both runners and nonrunners (p < .05). The hamstring muscles of the dominant leg were tighter than the hamstrings of the nondominant leg in all subjects (p < .05). In conclusion, long distance runners appear to have posterior muscle tightness in the lower extremity.

An Analysis of Individual Stretching Programs of Intercollegiate Athletes

In brief: Stretching may influence an athlete's susceptibility to injury. To evaluate individual stretching programs of intercollegiate athletes, 238 athletes (164 male, 74 female) in ten sports were surveyed about their stretching practices. Almost all of the athletes stretched, but to varying degrees. Only 39% stretched every day, and only 33% stretched both before and after activity. Overall, the women stretched significantly more than the men, but male swimmers appeared to have the most well-rounded stretching programs. Muscle groups that were stretched by the fewest athletes were the adductors, plantar flexors, hips, and neck. Comparison of these results with flexibility and injury in this study group could prove valuable.