A New Measuring Approach in Assessing Hamstring Flexibility: Reliability, Validity, and Applicability of Isolated Hamstring Flexibility Test

OBJECTIVE

This study was planned to determine the reliability, validity, and applicability of the isolated hamstring flexibility test (IHFT).

DESIGN

A cohort study (diagnosis); level of evidence, 2.

SETTING

It was performed in the research and application laboratory.

PARTICIPANTS

Seventy-five individuals aged 18 to 25 years, selected through simple probability random sampling, with a normal Beighton Horan and Joint Mobility Index scores, and who volunteered to participate, were included for evaluation.

INTERVENTIONS

On then first and third days, participants underwent muscle strength, sit-and-reach test, active knee extension test, IHFT for validity and reliability. Stretching exercises were prescribed as a home program for 31 patients with limited knee extension, and measurements were repeated at the end of the eighth week.

MAIN OUTCOME MEASURES

Sit-and-reach test, active knee extension test, IHFT.

RESULTS

The test-retest reliability was high (intraclass correlation coefficient, 0.993). Our test demonstrated validity when compared in terms of flexibility gained. A significant difference was found between pre-post stretching exercise training in all 3 tests ( P < 0.05).

CONCLUSION

It was observed that the IHFT is reliable and applicable in determining hamstring flexibility. Given the absence of another test specifically measuring hamstring flexibility in isolation, its indirect validity was established through analysis with other tests using the gold standard for assessing gains in hamstring flexibility.

Effects of post-exercise cold-water immersion on performance and perceptive outcomes of competitive adolescent swimmers

PURPOSE

To evaluate the effects of repeated use of cold-water immersion (CWI) during a training week on performance and perceptive outcomes in competitive adolescent swimmers.

METHODS

This randomized-crossover study included 20 athletes, who received each intervention [CWI (14 ± 1 °C), thermoneutral water immersion (TWI) (27 ± 1 °C) as placebo, and passive recovery (PAS)] three times a week between the land-based resistance training and swim training. The interventions were performed in a randomized order with a 1-week wash-out period. We tested athletes before and after each intervention week regarding swim (100 m freestyle sprints) and functional performance (flexibility, upper and lower body power, and shoulder proprioception). We monitored athlete's perceptions (well-being, heaviness, tiredness, discomfort and pain) during testing sessions using a 5-item questionnaire. Athlete preferences regarding the interventions were assessed at the end of the study. We used generalized linear mixed models and generalized estimating equations for continuous and categorical variables, respectively (intervention x time).

RESULTS

We found a time effect for swim performance (p = .01) in which, regardless the intervention, all athletes improved sprint time at post-intervention compared to baseline. There was an intervention effect for pain (p = .04) and tiredness (p = .04), but with no significant post-hoc comparisons. We found no significant effects for other outcomes. All athletes reported a preference for CWI or TWI in relation to PAS.

CONCLUSION

The repeated use of CWI throughout a training week did not impact functional or swim performance outcomes of competitive adolescent swimmers. Perceptive outcomes were also similar across interventions; however, athletes indicated a preference for both CWI and TWI.

Relation between Photogrammetry and Spinal Mouse for Lumbopelvic Assessment in Adolescents with Thoracic Kyphosis

The evaluation of the lumbopelvic region is a crucial point during postural assessment in childhood and adolescence. Photogrammetry (PG) and Spinal Mouse (SM) are two of the most debated tools to properly analyze postural alignment and avoid misleading data. This study aims to find out the best linear regression model that could relate the analytic measurements of the SM with one or more PG parameters in adolescents with kyphotic postures. Thirty-nine adolescents (female = 35.9%) with structural and non-structural kyphosis were analyzed (13.2 ± 1.8 years; 1.59 ± 0.12 m; 47.6 ± 11.8 kg) using the SM and PG on the sagittal plane in a standing and forward-bending position, allowing for the measurement of body vertical inclination, lumbar and pelvic alignment, trunk flexion, sacral inclination during bending, and hip position during bending. Lordosis lumbar angles (SM) were significantly (r = -0.379, r = -0.328) correlated with the SIPS-SIAS angle (PG) during upright standing, while in the bending position, the highest correlation appeared among the sacral-hip (SM) and the sacral tangent (ST_PG; r = -0.72) angles. The stepwise backward procedure was assessed to estimate the SM variability in the bending and standing positions. Only in the bending position did the linear regression model reach high goodness-of-fit values with two regressors (ST_PG η2=0.504, BMI η2=0.252; adjusted- R2 =0.558, p < 0.001, CCC = 0.972, r = 0.763). Despite gold-standard methods reducing error evaluation, physicians and kinesiologists may consider photogrammetry as a good method for spinal curve prediction.

Effects of a Pilates programme in spinal curvatures and hamstring extensibility in adolescents with thoracic hyperkyphosis: a randomised controlled trial

AIM

To evaluate the effects of a 9-month Pilates exercise programme on the sagittal spinal posture and hamstring extensibility of adolescents with thoracic hyperkyphosis.

DESIGN

Randomised controlled trial with blinded examiner.

PATIENTS

One-hundred and three adolescents with thoracic hyperkyphosis.

INTERVENTIONS

Participants were randomly placed into an experimental group which participated in a Pilates exercise programme implemented for a total of 38 weeks (two sessions/week, 15 min/session) (Pilates group (PG), sample = 49, or control group (CG), sample = 48).

MAIN OUTCOME MEASURES

The outcome measures were the thoracic curve in sagittal spinal curvature in relaxed standing, sagittal spinal curvatures and pelvic tilt in relaxed standing and sit-and-reach positions, and hamstring extensibility.

RESULTS

There was a significant adjusted mean difference between groups in favour of the PG in the thoracic curve in relaxed standing position (-5.6°, p = 0.003), pelvic tilt (-2.9°, p = 0.03) and all straight leg tests (p<0.001). The PG showed a significant change in thoracic curve (-5.9, p<0.001) and in lumbar angle (4.0, p = 0.001) in relaxed standing position and in all straight leg raise tests (+6.4 to +15°, p<0.0001).

CONCLUSIONS

The adolescents with thoracic hyperkyphosis from the PG had a decreased thoracic kyphosis in relaxed standing position, and improved hamstring extensibility as compared with the CG. More than 50% of the participants obtained kyphosis values inside normality, showing an adjusted mean difference between groups in the thoracic curve of about 73% of the baseline mean, resulting in a large improvement and high clinical importance.

TRIAL REGISTRATION NUMBER

NCT03831867.

Association between trunk flexibility and renal flow pulsatility in middle-aged and older adults

BACKGROUND

Recent clinical studies have indicated that poor trunk flexibility is associated with arterial stiffness in the aged. Arterial stiffness leads to elevated renal flow pulsatility, which accelerates age-related renal dysfunction and damages. However, data indicating the potential link between flexibility fitness and renal flow pulsatility are lacking. This study examined the cross-sectional association between trunk flexibility and renal flow pulsatility in middle-aged and older adults.

METHODS

A total of 175 middle-aged and older adults (aged 63 ± 9 years) were included in this study. Sit-and-reach tests (SRT) were performed to assess their trunk flexibility. Using a Doppler ultrasound, renal pulsatility index (PI) and resistive index (RI) were measured as parameters of renal flow pulsatility.

RESULTS

The study found that, in middle-aged and older adults, the SRT score was an independent determinant of renal PI (β = -0.134, P = 0.027) and RI (β = -0.135, P = 0.027). In the one-way analysis of covariance (ANCOVA), the renal PI and RI in the older group with a lower SRT score were found to be significantly higher than those in the middle-aged group.

CONCLUSIONS

Trunk flexibility is an independent determinant of renal flow pulsatility in middle-aged and older adults.

Repeated Massage Improves Swimmers' Perceptions during Training Sessions but Not Sprint and Functional Performance: A Randomized Controlled Trial

This study aimed to investigate the effects of repeated massage adjusted for swimmers' training on the perceptive, functional, and performance outcomes of a sprint. We also investigated the effects of a single short massage on swimmers' self-reported perceptions after resistance training. This cross-over randomized controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis included 19 male and female competitive swimmers between 12 and 20 years old. Participants were subjected to three 12-min interventions over a week between resistance and swim training and monitored regarding training load and perceptions. After the intervention week we assessed: perceptive (well-being, heaviness, tiredness, discomfort, and pain), performance (sprint time, FINA points, and stroke characteristics), and functional outcomes (flexibility, squat jump, bench press, proprioception), in addition to athlete beliefs and preferences. A massage was defined as consisting of sliding movements on the arms, back, and anterior thigh, with metronomic rhythm control (1:1), and was divided into two protocols: superficial massage (SM) (light touch) and deep massage (DM) (light, moderate, intense effleurage) while the control (CON) rested. After repeated massage (SM and SM), participants had less chances to report tiredness, and they also maintained perceptions of well-being while CON got worse throughout the week. However, we found evidence of worsening of the perceptions of heaviness and pain at the main stages of the swim training for the massage groups. SM and DM had no effects over sprint and functional performance. Our results suggest that the swimmers were able to train harder with no harm to recovery.

Fiabilidad y validez de las pruebas v-sit-and-reach y toe-touch en preescolares

Este estudio de carácter psicométrico tuvo como objetivo evaluar la fiabilidad y validez de las pruebas V-Sit and Reach (VS) y Toe –Touch (TT) en población preescolar. De un total inicial de 158 participantes, 132 realizaron las pruebas en tres ocasiones. La prueba de elevación pasiva de la pierna recta (PSLR) se usó como indicador de validez. Ambas pruebas mostraron una fiabilidad excelente (CCI=0,91-0,93 para el VS; CCI=0,93-0,97 para el TT). Se observaron correlaciones estadísticamente significativas (p<0,05) entre ambas herramientas y la prueba de PSLR para todos los grupos analizados, excepto en el TT en el grupo de 3 años de edad. En conclusión, estos hallazgos indican que tanto el VS como el TT son pruebas con una validez moderada para evaluar la flexibilidad de la parte inferior del cuerpo en preescolares. La prueba VS puede ser preferible sobre la prueba TT.

Influence of biological maturation status on selected anthropometric and physical fitness variables in adolescent male volleyball players

Background

The identification of sport talent among adolescent athletes is a topic that in recent years has been a major focus of interest for both the scientific community and sport managers. Both anthropometry and physical performance through fitness tests have demonstrated to be key elements. Biological maturation, due to its influence on anthropometric variables and physical fitness, has also been studied in relation to sport talent identification.

Objective

To analyse differences according to biological maturation status in anthropometric characteristics and performance in physical fitness tests, and to determine which variables predict better performance in physical fitness tests in adolescent volleyball players.

Methods

A cross-sectional design was followed to collect the data. A total of 48 male sub-elite volleyball players (14.17 ± 0.73 years) completed a socio-demographic and sports ad hoc questionnaire. Anthropometric variables were measured following the guidelines of the International Society for the Advancement in Kinanthropometry (ISAK) including four basic measurements (body mass, height, sitting height and arm span); eight skinfolds (triceps, biceps, subscapular, iliac crest, supraspinale, abdominal, thigh and calf); four girths (arm relaxed, flexed and tensed arm, middle thigh and calf); five breadths (biacromial, biileocrestal, humerus, femur and bi-styloid); three lengths (acromiale-radiale, radiale-stylion and stylion-medio dactilion); and a height (ilioespinale). Physical fitness was assessed, including the sit-and-reach, back scratch, long jump, medicine ball throw, counter movement jump (CMJ), 20 meters sprint, and agility tests. Furthermore, maturity offset and age at peak height velocity (APHV) was calculated.

Results

Significant differences were found in the body mass (Mean Difference, MD = 20.86-30.75), height (MD = 11.72-19.09), sitting height (MD = 4.27-10.27), arm span (MD = 12.91-20.78), body mass index (MD = 3.72-5.63), upper limb length (MD = 7.76), corrected muscle girths (MD = 2.06-9.31), ∑6 and 8 skinfolds (MD = 3.67-50.21) fat mass and percentage (MD = 0.30-11.58), muscle (MD = 4.13-10.64) and bone mass (MD = 1.61-3.54) (p < 0.001-0.030), showing higher values the early maturers. In the physical fitness tests, significant differences were observed in the medicine ball throw (MD = 1.26-2.80) and in CMJ power (MD = 156.71-379.85) (p < 0.001). Regression models identified fat mass percentage predicted worse physical test performance (p < 0.001), while age, maturation offset, muscle and bone variables were predictors of better physical performance (p < 0.001).

Conclusions

Significant differences based upon the stages of biological maturation were found in the anthropometric and physical condition variables in favor of the players whose maturation process was more advanced, with the variables related to fat and adipose, muscle and bone development conditioning their performance in the physical condition tests.

The Effect of Age, Biological Maturation and Birth Quartile in the Kinanthropometric and Physical Fitness Differences between Male and Female Adolescent Volleyball Players

BACKGROUND

Differences in kinanthropometric and physical fitness performance between boys and girls usually start during adolescence, as a result of the changes in the hormonal environment that occur with the advance of age and biological maturation; Methods: A total of 96 1st Regional Division players adolescent volleyball players, 48 males, (age = 14.17 ± 1.00 years-old) and 48 females (age = 14.41 ± 1.21 years-old) underwent a kinanthropometric assessment, were asked to perform different physical fitness test and to complete a questionnaire. Chronological age, maturity offset, age at peak height velocity (APHV), and birth quartile were calculated; Results: Statistical differences were observed between male and female players in the APHV (p < 0.001). Male players showed higher values in the bone and muscle-related variables (p < 0.001-0.040), as well as in the strength and power production-related physical tests (p < 0.001-0.012), while the female showed higher values in the fat-related variables (p = 0.003-0.013), and performed better in the flexibility tests. Age, maturity offset, and birth quartile showed to have statistical influence in the differences found between sex groups; Conclusions: There is a clear influence of age and biological maturation on the differences found between sexes in adolescent volleyball players that could be taken into account regarding grouping in early stages.

The Case for Retiring Flexibility as a Major Component of Physical Fitness

Flexibility refers to the intrinsic properties of body tissues that determine maximal joint range of motion without causing injury. For many years, flexibility has been classified by the American College of Sports Medicine as a major component of physical fitness. The notion flexibility is important for fitness has also led to the idea static stretching should be prescribed to improve flexibility. The current paper proposes flexibility be retired as a major component of physical fitness, and consequently, stretching be de-emphasized as a standard component of exercise prescriptions for most populations. First, I show flexibility has little predictive or concurrent validity with health and performance outcomes (e.g., mortality, falls, occupational performance) in apparently healthy individuals, particularly when viewed in light of the other major components of fitness (i.e., body composition, cardiovascular endurance, muscle endurance, muscle strength). Second, I explain that if flexibility requires improvement, this does not necessitate a prescription of stretching in most populations. Flexibility can be maintained or improved by exercise modalities that cause more robust health benefits than stretching (e.g., resistance training). Retirement of flexibility as a major component of physical fitness will simplify fitness batteries; save time and resources dedicated to flexibility instruction, measurement, and evaluation; and prevent erroneous conclusions about fitness status when interpreting flexibility scores. De-emphasis of stretching in exercise prescriptions will ensure stretching does not negatively impact other exercise and does not take away from time that could be allocated to training activities that have more robust health and performance benefits.

Internal Risk Factors for Low Back Pain in Pole Vaulters and Decathletes: A Prospective Study

Background:

Pole vaulters and decathletes frequently experience several types of injuries to their lower back, often resulting in mechanical low back pain (LBP). However, the risk factors for the occurrence of LBP in these athletes have not been defined.

Purpose:

To determine the physical factors that relate to LBP occurrence for collegiate pole vaulters and decathletes.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

We observed 31 pole vaulters and decathletes for 1 year. At the start of the observation period, isokinetic flexion and extension muscle strength of the knee and hip joints were recorded along with active and passive range of motion (ROM) and muscle tightness. Participants were then divided into 2 groups using the median value of each measurement: those below the median (low group) and those above the median (high group). The log-rank test was used to compare LBP occurrence between the low group and high group for all measurements. Multivariate regression analyses were thereafter applied using the Cox proportional hazards regression.

Results:

Log-rank tests revealed a statistically significant change in the survival curve for the occurrence of LBP in the participants with chronic LBP (P = .037), the low group for hip flexion peak torque per body weight on the non-takeoff leg (P = .047), and the low group for passive hip flexion angle on both legs (takeoff leg: P = .034; non-takeoff leg: P = .023). In addition, log-rank tests revealed a statistically significant change in the survival curve for the occurrence of LBP in the low group for passive hip extension angle on the takeoff leg only for the participants without chronic LBP (P = .014).

Conclusion:

It may be necessary to acquire sufficient ROM and hip flexion to prevent LBP occurrence in pole vaulters and decathletes.

Back Pain Related with Age, Anthropometric Variables, Sagittal Spinal Curvatures, Hamstring Extensibility, Physical Activity and Health Related Quality of Life in Male and Female High School Students

Spinal pain (SP) is widely extended among adolescents. The origin of SP can be multifactorial; thus, the present study aimed to estimate the prevalence and risk of SP in high school students and to determine the differences in sagittal spinal curvatures and pelvic tilt, hamstring extensibility, age, anthropometric variables and healthy lifestyle habits dependent on SP between sexes. Two hundred seventy-three teenagers took part in this cross-sectional study. Age, sagittal spinal curvatures, hamstring extensibility, physical activity, sedentary lifestyle, anthropometric variables and health related quality of life (HRQL) were recorded. SP was reported by 16.12% of adolescents. Differences were observed in the HRQL according to SP (p < 0.05). Participants without SP were less sedentary (22.12%) and younger (13.10 years old) than participants with SP (40.91% and 13.66, respectively) (p < 0.05). A logistic regression model showed that both variables were significantly collinear (VIF = 1.01; Durbin-Watson = 2.10). Subjects with low back pain (LBP) had a higher weight, body max index, and hip girth than subjects without pain (p < 0.05). A misalignment in the lumbar spine was associated with LBP for males (Cramer’s V = 0.204, p = 0.022). In conclusion, adolescents with SP were older and had a lower HRQL in all dimensions. SP could be predicted according to age and sedentary habits.

Hamstring extensibility differences among elite adolescent and young dancers of different dance styles and non-dancers

Background

Hamstrings have been analyzed extensively due to their tendency to shorten and their effect in the lumbo-pelvic dynamics and the sagittal position of the spine in trunk flexion with extended knees positions. It has been demonstrated that practicing a certain sport results in long-term changes in hamstring extensibility. Despite this, adequate extensibility of the hamstring musculature is essential for the dancer’s performance. Several studies have found differences in the extensibility of the hamstrings depending on the dance style, but none have compared ballet, Spanish dance and modern dance. The purpose of the present research was to analyze the differences in hamstring extensibility among professional dance students based on dance style practiced and non-dancers.

Methods

The sample was comprised of 210 students from the Professional Dance Conservatory (70 for ballet, 70 for Spanish dance and 70 for modern dance) and 70 non-dancers. For the assessment of hamstring extensibility, the angle in the passive and active straight leg raise (PSLR and ASLR, respectively) test, and the scores of the pelvic tilt in sit-and-reach (SR) test and the toe-touch (TT) test were randomly conducted.

Results

The results showed significant differences for all the tests according to group (p < 0.001). In the PSLR and ASLR test, for both legs, and in the pelvic tilt in the SR test, the ballet dancers showed greater ranges of hamstring extensibility than the modern dancers and Spanish dancers (p ≤ 0.001). In the distance in the SR test and in the pelvic tilt in the TT test, the ballet dancers obtained higher values than the Spanish dancers (p = 0.004 and p = 0.003, respectively). The modern dancers showed higher ranges of hip flexion than the Spanish dancers in the ASLR test for both legs and in the pelvic tilt in the SR test (p from 0.007 to <0.001). Dancers showed significantly higher hamstring extensibility than non-dancers in all the tests (p < 0.001).

Conclusions

The systematic practice of dance, regardless of the style, seems to lead to high ranges of hamstring extensibility. Ballet dancers have the greatest hamstring extensibility.

The Federated Practice of Soccer Influences Hamstring Flexibility in Healthy Adolescents: Role of Age and Weight Status

The aim of this study was to compare the hamstring flexibility between federated soccer and non-federated adolescents, and also to evaluate the effect of age and weight status on hamstring flexibility. The participants were 234 students (11–18 years old) divided into: (i) G1: non-federated (n = 127), and (ii) G2: federated in soccer (n = 107). The deep flexion of the trunk (DF) test and the sit and reach test (SRT) were performed. G2 showed higher values for the DF and SRT compared to G1 (p < 0.05). Both flexibility tests correlated positively (r = 0.4, p < 0.001). Body mass index (BMI) was negatively correlated with the DF test (r = −0.3, p < 0.001), but not with the SRT. Divided by BMI, the underweight and normal weight groups had higher scores in the DF test compared with the overweight and obese groups (p < 0.001). BMI was negatively correlated with hamstring flexibility. Federated soccer students present higher scores of hamstring flexibility.

Selection and promotion processes are not associated by the relative age effect in an elite Spanish soccer academy

The aim of this study was to analyze the influence of the relative age effect (RAE) on the selection and promotion processes in an elite soccer academy. One hundred and eleven elite youth players who belonged to an elite soccer club from the Spanish "La Liga" participated in this study. Players were classified into three age-categories: under 14 years (U14), under 16 years (U16) and under 18 years (U18); and they were also classified in quartiles based on their date of birth (i.e., January-March, Q1; April-June, Q2; July-September, Q3; October-December, Q4). In addition, two further classification criteria were established based on the selection (i.e., selected and non-selected players) and promotion (i.e., promoted and non-promoted players) processes. The main results showed that in U14 and U16 age-categories, players born early in the year were over-represented compared to players born late in the year, although birth-distribution was not associated with the likelihood of a player to be selected or promoted. In addition, less fat in sum skinfolds, less percentage of fat, higher percentage of muscle and lower endomorphy and mesomorphy components were showed in U14 selected players, in comparison with non-selected players. Likewise, better sprint performance was found in U16 selected players versus non-selected ones. However, no significant differences on anthropometry, body composition, somatotype and physical performance were found between promoted and non-promoted players. Therefore, our results suggest there is need for coaches to reorient their talent identification programs in order to make sure that players selected to continue playing in the club have the potential to promote to the excellence in soccer.

Musculoskeletal Screening to Identify Female Collegiate Rowers at Risk for Low Back Pain

CONTEXT

Rowers are at risk for overuse injuries, including low back pain (LBP). Defining the utility of screening tests for identifying those at risk for LBP can aid in the development of guidelines for injury prevention.

OBJECTIVE

To determine if the Functional Movement Screen (FMS) and impairments can identify rowers at risk for developing LBP.

DESIGN

Prospective cohort study.

SETTING

Athletic training room.

PATIENTS OR OTHER PARTICIPANTS

A total of 31 National Collegiate Athletic Association Division I, female, open-weight rowers (age = 19.9 ± 1.4 years, height = 163.6 ± 30.8 cm, mass = 84.1 ± 37.63 kg); coxswains were excluded.

MAIN OUTCOME MEASURE(S)

We assessed the FMS and 5 impairment measures of the Star Excursion Balance Test, closed kinetic chain dorsiflexion range of motion, and the plank, Sorensen, and sit-and-reach tests before the fall season. Low back pain injuries were tracked by the sports medicine staff. Impairment measures were compared between the injured and uninjured athletes. The FMS cutoff score that discriminated injured from uninjured rowers was determined using a receiver operating characteristic curve analysis. Impairments were compared between those at a higher versus lower risk of LBP.

RESULTS

Eighteen rowers sustained an LBP injury. No differences in FMS or impairments between groups were demonstrated. The FMS receiver operating characteristic curve analysis cutoff score was 16 points (area under the curve = 0.60, specificity = 0.67, risk ratio = 1.4 [95% confidence interval = 0.91, 2.11]). Rowers with an FMS score ≤16 had a shorter plank-test time (109.5 ± 60.2 seconds) than those with less risk (175.3 ± 98.6 seconds, mean difference = 65.9 seconds, 95% confidence interval = -129.4, -2.3; P = .043).

CONCLUSIONS

Those with an FMS score ≤16 had a shorter plank-test hold time, indicating that a lack of core endurance may contribute to the increased risk of LBP in female rowers. An FMS score ≤16 indicated a small increased risk (1.4) of developing LBP compared with rowers who had scores >16; however, the FMS is not recommended for widespread screening of female rowers because the risk ratio was relatively small and had a wide 95% confidence interval.

Influence of the Box Dimensions on the Reliability and Validity of the Sit and Reach in Preschoolers

Ayán Pérez, C, Martínez de Quel, Ó, Álvarez Pérez, S, and González Baamonde, S. Influence of the box dimensions on the reliability and validity of the sit and reach in preschoolers. J Strength Cond Res 34(9): 2683-2692, 2020-This study aimed at analyzing the reliability and validity of the sit and reach (SR) test, when it was performed with a standard SR (SSR) or an adapted SR (ASR) box in preschoolers. To accomplish this, both tests were administered 3 times (familiarization, test, and retest) to a group of 148 children (mean age, 4.99 ± 0.94 years; 49.3% girls), with a week interval between each assessment. The obtained results in each test were compared with those obtained in the passive straight leg raise (PSLR) test with the aim of identifying their construct validity. The internal consistency was found to be between good and excellent for the SSR (α: 0.83-0.92) and excellent for the ASR (α: 0.92-0.96). The SSR showed a good and a fair reliability (intraclass correlation coefficient [ICC], 0.71-0.86), whereas the ASR showed an excellent reliability (ICC, 0.90-0.94) except for the 3-year-old children group (ICC, 0.84). Absolute reliability was excellent for the ASR, whereas the SSR yielded higher SEM and minimum detectable change percentage values. Regarding the criterion-related validity, statistically significant fair correlations were observed between both SR tests and the PSLR test. The ASR yielded higher levels of statistical significance as well as greater correlation coefficients than the SSR. This finding indicates that when it comes to assess flexibility through a low cost and easy-to-implement lineal test in preschoolers, it is advisable to use the SR with a box of reduced dimensions.

Comparison of a 12-Week Whole-Body Exergaming Program on Young Adults: Differentiation in Flexibility, Muscle Strength, Reaction Time, and Walking Speed Between Sexes

This study aimed to investigate the effects of exergaming on flexibility, muscle strength, reaction time, and walking speed of adults within sex differences. Fifty-four individuals participated in a 12-week exergaming program. Three 30-min sessions were conducted each week. Baseline and post-intervention assessments were done using the sit-and-reach and bend-over tests for flexibility, hand-held dynamometer for muscle strength, auditory and visual reaction time machine for reaction time, and 5-meter walk test for walking speed. There were no significant changes in the sit-and-reach, bend-over test, and auditory-visual reaction time for either gender ( p > .05) with the intervention. Walking speed and muscle strength improved after exergaming in both sexes ( p < .05). The study showed that the video gaming intervention led to significant and equal improvements in muscle strength and walking speed for both sexes; however, it had no impact on flexibility and auditory-visual reaction time.

Instrument-assisted soft tissue mobilization and proprioceptive neuromuscular facilitation techniques improve hamstring flexibility better than static stretching alone: a randomized clinical trial

Objectives: Tight hamstrings contribute to inefficiency of movement and increased risk for injury. Static stretching is the most common intervention for this problem, but the use of alternatives like instrument-assisted soft tissue mobilization (IASTM) and proprioceptive neuromuscular facilitation (PNF) is increasing among clinicians. This study examined two prospective studies with the common aim of demonstrating the effectiveness of IASTM or PNF over static stretching for improving hamstring tightness. Methods: Nondisabled adults were recruited on a university campus. IASTM study: N = 17 (11 males and 6 females). PNF study: N = 23 (7 males and 16 females). Hip flexion range of motion was measured with a passive straight leg raise (for IASTM) or active straight leg raise (for PNF) before and after stretching. Participants performed a self-static stretch on one leg and received the alternative intervention on the contralateral leg. The two studies were analyzed separately for reliability indices and significant differences between interventions. Results: Hip flexion measures showed good reliability in both studies (intraclass correlation coefficient = 0.97) with a minimal detectable change of <4.26. Both studies showed significant interactions between time and intervention (p < 0.05). Follow-up analyses revealed PNF and IASTM interventions resulted in greater increases in hip flexion range than static stretching. Discussion: These findings demonstrate the effectiveness of PNF and IASTM techniques over static stretching for hamstring flexibility. These interventions provide more efficient alternatives for improving flexibility in the clinic, allowing greater progress in a shorter period of time than an equivalent static stretching program. Level of Evidence: 1b.

Effects of Latin style professional dance on the spinal posture and pelvic tilt

BACKGROUND

Systematic repetition postures adopted during trainings could generate alterations in the sagittal spinal curvatures.

OBJECTIVE

The purposes were: 1) to analyse the sagittal spinal curvatures and pelvic tilt in Latin American style dancers; 2) to compare the spinal sagittal mobility and hamstring muscle extensibility between Latin American style dancers and non-dancers; and 3) to evaluate the influence of wearing dance shoes upon the sagittal spine posture in standing.

METHODS

A total of 20 Latin American style professional dancers and 20 non-dancers (control group) were evaluated during standing, relaxed sitting, maximal trunk flexion with knees flexed and extended, lying prone, and maximal trunk extension. Additionally, dancers were analysed while standing barefoot, and wearing heeled-shoes, during forward walking and the paso-doble posture. The hamstring muscle extensibility was evaluated by the active knee extension test.

RESULTS

The spinal morphology in Latin American style professional dancers is characterised by lower thoracic kyphosis, lumbar lordosis and anterior pelvic tilt in the standing posture as well as a flexible spine, especially in flexion postures, in addition to suitable hamstring muscle extensibility.

CONCLUSIONS

The spinal morphology of Latin American style professional dancers is characterised by lower thoracic kyphosis and lumbar lordosis and anterior pelvic tilt in the standing posture as well as a flexible spine, especially in flexion postures, and suitable hamstring muscle extensibility.

Differences in Anthropometry, Biological Age and Physical Fitness Between Young Elite Kayakers and Canoeists

The aim of this study was to determine the anthropometric and physical characteristics of youth elite paddlers and to identify the differences between kayakers and canoeists. A total of 171 male paddlers (eighty-nine kayakers and eighty-two canoeists), aged 13.69 ± 0.57 years (mean ± SD) volunteered to participate in this study. The participants completed basic anthropometric assessments (body mass, stretch stature, sitting height, body mass index, maturity level, sum of 6 skinfolds and fat mass percentage) as well as a battery of physical fitness tests (overhead medicine ball throw, counter movement jump, sit-and-reach and 20 m multi-stage shuttle run tests). The anthropometric results revealed a significantly larger body size (stretch stature and sitting height) and body mass in the kayakers (p < 0.01) as well as a more mature biological status (p = 0.003). The physical fitness level exhibited by the kayakers was likewise significantly greater than that of the canoeists, both in the counter movement jump and estimated VO2max (p < 0.05), as well as in the overhead medicine ball throw and sit-and-reach test (p < 0.01). These findings confirm the more robust and mature profile of youth kayakers that might be associated with the superior fitness level observed and the specific requirements of this sport discipline.

Return to play after hamstring injuries in football (soccer): a worldwide Delphi procedure regarding definition, medical criteria and decision-making

There are three major questions about return to play (RTP) after hamstring injuries: How should RTP be defined? Which medical criteria should support the RTP decision? And who should make the RTP decision? The study aimed to provide a clear RTP definition and medical criteria for RTP and to clarify RTP consultation and responsibilities after hamstring injury. The study used the Delphi procedure. The results of a systematic review were used as a starting point for the Delphi procedure. Fifty-eight experts in the field of hamstring injury management selected by 28 FIFA Medical Centres of Excellence worldwide participated. Each Delphi round consisted of a questionnaire, an analysis and an anonymised feedback report. After four Delphi rounds, with more than 83% response for each round, consensus was achieved that RTP should be defined as ‘the moment a player has received criteria-based medical clearance and is mentally ready for full availability for match selection and/or full training’. The experts reached consensus on the following criteria to support the RTP decision: medical staff clearance, absence of pain on palpation, absence of pain during strength and flexibility testing, absence of pain during/after functional testing, similar hamstring flexibility, performance on field testing, and psychological readiness. It was also agreed that RTP decisions should be based on shared decision-making, primarily via consultation with the athlete, sports physician, physiotherapist, fitness trainer and team coach. The consensus regarding aspects of RTP should provide clarity and facilitate the assessment of when RTP is appropriate after hamstring injury, so as to avoid or reduce the risk of injury recurrence because of a premature RTP.

Hamstring-and-Lower-Back Flexibility in Male Amateur Soccer Players

OBJECTIVE

This study investigated the hamstring-and-lower-back flexibility (HLBF) of male adult amateur soccer players, using the sit-and-reach test (SRT), with a view to obtaining population-based reference values and to determining whether SRT scores are associated with player characteristics.

DESIGN

Cross-sectional cohort study.

SETTING

Teams from high-level Dutch amateur soccer competitions were recruited for participation.

PARTICIPANTS

Dutch male high-level amateur field soccer players (n = 449) of age 18 to 40 years. Players with a hamstring injury at the moment of SRT-measurement or any other injury that prevented them from following the SRT protocol were excluded.

MAIN OUTCOME MEASURES

Sit-and-reach test scores were measured and then population-based reference values were calculated as follows: >2SD below mean (defining "very low" HLBF), 1SD-2SD below mean ("low" HLBF), 1SD below mean to 1SD above mean ("normal" HLBF), 1SD-2SD above mean ("high" HLBF), and >2SD above mean ("very high" HLBF). Whether SRT scores were correlated with player characteristics was determined using a Pearson correlation coefficient or Spearman rho.

RESULTS

Sit-and-reach test scores ranged from 0 to 43.5 cm (mean 22.0 cm, SD 9.2). The cutoff points for population-based reference values were <3.5 cm for "very low", 3.5 to 13.0 cm for "low", 13.0 to 31.0 cm for "normal", 31.0 to 40.5 cm for "high", and >40.5 cm for "very high". Sit-and-reach test scores were significantly associated with players' height (ρ = -0.132, P = 0.005), body mass index (r = 0.114, P = 0.016), and history of anterior cruciate ligament surgery (P < 0.001).

CONCLUSIONS

This study is the first to describe the HLBF of amateur soccer players. The SRT reference values with cutoff points may facilitate evidence-based decision making regarding HLBF, and the SRT might be a useful tool to assess injury risk, performance, or for diagnostic purposes.

Effects of Acute Fatigue of the Hip Flexor Muscles on Hamstring Muscle Extensibility

The purpose of the present study was to evaluate the influence of acute fatigue of the hip flexor muscles on scores attained in tests frequently used in literature to measure hamstring muscle extensibility, namely the passive straight leg raise (PSLR), active straight leg raise (ASLR), passive knee extension (PKE), active knee extension (AKE), sit-and-reach (SR) and toe-touch (TT) tests. A total of seventy-five healthy and recreationally active adults voluntarily participated in this study. To reach fatigue, the participants actively lifted their legs alternately as many times as possible. In the passive tests, the results were 7.10 ± 5.21° and 5.68 ± 4.54° higher (p < 0.01) for PSLR and PKE tests, respectively, after acute fatigue. However, in the ASLR test, the results were lower post-fatigue than pre-fatigue (mean difference = -5.30° ± 9.51°; p < 0.01). The AKE, SR and TT tests did not show significant differences between pre- and post-fatigue (p > 0.05). Moderate (r = 0.40) to high (r = 0.97) correlation coefficients were found, which were statistically significant among all the measured flexibility tests both pre- and post-fatigue. In conclusion, the active implication of the hip flexor muscles until reaching fatigue had acute influences on the results of the PSLR, PKE and ASLR tests, but not on the results of the AKE, SR and TT tests. It is recommended to use the AKE test to assess hamstring muscle extensibility in situations where athletes show fatigue in their hip flexor muscles.