Accuracy and feasibility of video analysis for assessing hamstring flexibility and validity of the sit-and-reach test

Modified Functional Reach Test: Upper-Body Kinematics and Muscular Activity in Chronic Stroke Survivors

Effective control of trunk muscles is fundamental to perform most daily activities. Stroke affects this ability also when sitting, and the Modified Functional Reach Test is a simple clinical method to evaluate sitting balance. We characterize the upper body kinematics and muscular activity during this test. Fifteen chronic stroke survivors performed twice, in separate sessions, three repetitions of the test in forward and lateral directions with their ipsilesional arm. We focused our analysis on muscles of the trunk and of the contralesional, not moving, arm. The bilateral activations of latissimi dorsi, trapezii transversalis and oblique externus abdominis were left/right asymmetric, for both test directions, except for the obliquus externus abdominis in the frontal reaching. Stroke survivors had difficulty deactivating the contralesional muscles at the end of each trial, especially the trapezii trasversalis in the lateral direction. The contralesional, non-moving arm had muscular activations modulated according to the movement phases of the moving arm. Repeating the task led to better performance in terms of reaching distance, supported by an increased activation of the trunk muscles. The reaching distance correlated negatively with the time-up-and-go test score.

Estimation of Health-Related Physical Fitness Using Multiple Linear Regression in Korean Adults: National Fitness Award 2015-2019

Continuous health care and the measurement of health-related physical fitness (HRPF) is necessary for prevention against chronic diseases; however, HRPF measurements including laboratory methods may not be practical for large populations owing to constraints such as time, cost, and the requirement for qualified technicians. This study aimed to develop a multiple linear regression model to estimate the HRPF of Korean adults, using easy-to-measure dependent variables, such as gender, age, body mass index, and percent body fat. The National Fitness Award datasets of South Korea were used in this analysis. The participants were aged 19-64 years, including 319,643 male and 147,600 females. HRPF included hand grip strength (HGS), flexibility (sit and reach), muscular endurance (sit-ups), and cardiorespiratory fitness (estimated VO_2max ). An estimation multiple linear regression model was developed using the stepwise technique. The outlier data in the multiple regression model was identified and removed when the absolute value of the studentized residual was ≥2. In the regression model, the coefficient of determination for HGS (adjusted R ²: 0.870, P < 0.001), muscular endurance (adjusted R ²: 0.751, P < 0.001), and cardiorespiratory fitness (adjusted R ²: 0.885, P < 0.001) were significantly high. However, the coefficient of determination for flexibility was low (adjusted R ²: 0.298, P < 0.001). Our findings suggest that easy-to-measure dependent variables can predict HGS, muscular endurance, and cardiorespiratory fitness in adults. The prediction equation will allow coaches, athletes, healthcare professionals, researchers, and the general public to better estimate the expected HRPF.

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.

Effect of hamstring tissue flossing during warm-up on sit and reach performance

BACKGROUND

Tissue flossing, also called voodoo flossing, is becoming a popular adjunct to athletic training to improve joint range of motion and muscle strength. The authors of this technique believe that tissue flossing can be used during warm-up. This study investigated the effect of tissue flossing during warm-up on the range of motion in the sit and reach test.

METHODS

The study enrolled 40 recreational athletes divided into an experimental and control group consisting of 20 participants each. The range of trunk flexion was assessed with the sit and reach test. Participants were tested before as well as immediately and 15, 30 and 45 minutes after completing the 9-minute warm-up. During the warm-up, athletes in the experimental group wore a floss band on the thigh muscles, while athletes in the control group exercised without wearing a floss band.

RESULTS

The sit and reach test revealed an improved range of motion after the warm-up in both groups (p<0.05). The improvement was noted at all time points. Regression analysis showed no effect of any of the study parameters (group assignment, sex, age, body mass index, pain intensity on a visual analogue scale) on the improvement in the sit and reach test results.

CONCLUSIONS

The similar results obtained in both groups indicate that there may not be a rationale for using tissue flossing during warm-up to improve trunk and hip flexibility.

Association of Physical Fitness Performance Tests and Anthropometric Indices in Taiwanese Adults

Background

The association between physical fitness performance tests and anthropometric indices is not clear. The study aims to explore the association between physical fitness performance and anthropometric indices in Taiwanese community-dwelling adults. This may help in monitoring anthropometric indices to improve physical fitness.

Methods

We recruited 2216 participants aged 23–64 years between 2014 and 2017. Physical fitness performance, including abdominal muscular endurance (60-s sit-up test), flexibility (sit-and-reach test), and cardiorespiratory endurance (3-min step test), was evaluated in all participants. The association of the physical fitness performance and anthropometric indices, including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), was analyzed using linear regression, with adjustments for age and gender.

Results

Body mass index was negatively associated with abdominal muscular endurance (p < 0.001) and cardiorespiratory endurance (p < 0.001). Neither BMI, WC, WHR, nor WHtR were significantly associated with flexibility. Abdominal muscle endurance, flexibility, and cardiorespiratory endurance were significantly lower in obese participants when obesity was defined using a BMI of ≥27, 30, and 35 kg/m². Participants with central obesity that was defined as WC ≥ 90 cm in men and 80 cm in women and WHtR ≥ 0.6 had lower abdominal muscular endurance than those without central obesity.

Conclusion

Body mass index is associated with abdominal muscular endurance and cardiorespiratory endurance in a reverse J-shaped manner. None of the anthropometric indices are significantly associated with flexibility. Obesity defined by BMI is linked to worse physical fitness performance and obesity defined using WHtR is linked to lower abdominal muscular endurance in Taiwanese community-dwelling adults.

Effect of myofascial release on lower limb range of motion, sit and reach and horizontal jump distance in male university students

OBJECTIVE

Evaluate the effects of Myofascial release (MR) on lower limb ROM, sit and reach and horizontal jump distance in male university students.

STUDY DESIGN

Quasi-experimental study.

BACKGROUND

MR is a technique that aims to stretch fascia to increase range of motion (ROM), relieve pressure points and improve performance. However, there is limited evidence of its actual effects on flexibility and physical performance.

METHODS

Twenty-one uninjured, male university students received MR (11 on the first session and the other 10 on the second session 24 h later), completed lower limb ROM assessments, the sit and reach and the horizontal jump tests in a randomized order. MR was performed before the tests with a myofascial stick in the anterior and posterior aspects of the right and left thigh and calf muscles. Each muscle group was massaged for 90 s, totaling 9 min of MR. The testing conditions with MR and without MR were compared using Student t-tests and the effect sizes (ES) were calculated.

RESULTS

There were no significant differences between the testing conditions on horizontal jump distance. However, the sit and reach distance (28 ± 9 vs. 32 ± 9 cm, p = 0.001; ES = 0.44), left hip extension (10 ± 2 vs. 8 ± 2°, p = 0.006; ES = 1.00) and left plantar flexion (36 ± 7 vs. 39 ± 7°, p = 0.044; ES = 0.43) were higher with MR.

CONCLUSIONS

MR increased sit and reach distance, left hip extension and plantar flexion, but it did not affect horizontal jump distance in uninjured, male university students.

Injuries and physical characteristics affecting swimmer participation in the Olympics: A prospective survey

OBJECTIVE

To identify injuries and physical characteristics affecting swimmers' performance.

DESIGN

Prospective study.

SETTING

Laboratory-based.

PARTICIPANTS

Sixty-four Rio Olympic candidates (36 men, 28 women), who were high level swimmers ranked among the top 32 in the 2014 World Ranking in swimming. The participants were categorized into the Olympian group (n = 25), swimmers who were consecutively selected for the Olympic team, and the non-Olympian group (n = 39), swimmers who were not.

MAIN OUTCOME MEASURES

Four months prior to the Olympic qualification in 2016, an orthopedist and two physical therapists evaluated injuries and 11 physical characteristics of the swimmers. The prevalence of total overuse injuries, shoulder and low back injury, and physical characteristics were compared between the two groups.

RESULTS

The female swimmers in the non-Olympian group had a 53.3% prevalence of total overuse injuries, which was significantly higher than that of those in the Olympian group with 15.4% (p = 0.037). The prevalence of total over use injuries in male swimmers in both the Olympian and non-Olympian groups was 41.7%. Female Olympian group showed that the shoulder external rotation range of motion was significantly less than that of non-Olympian group (97.8 ± 5.7 and 103.6 ± 7.3, p = 0.046).

CONCLUSIONS

In female swimmers, total overuse injuries four months before an important competition influence their performance at the event.

Associations between sensorimotor gating mechanisms and athletic performance in a variety of physical conditioning tests

PURPOSE

The elite athlete is fine-tuned all around to deliver favorable results in sporting events. In this study, we address the question of whether basic movements-such as reflexes-and heterogeneous attentional modulation components-such as sensorimotor gating mechanisms-are also tuned up to maximize the results of middle-distance runners in physical conditioning tests.

METHODS

We selected an array of professional middle-distance runners and healthy counterparts that were submitted to measurement of (1) physical conditioning parameters, including somatotype, jump, strength, and flexibility tests; and (2) sensorimotor gating mechanisms, including acoustic startle reflex, prepulse inhibition, and habituation.

RESULTS

Our results showed athletes scored better on the athletic tests compared to controls, as expected. They also exhibited a lower startle amplitude, while maintaining higher prepulse inhibition values. They reacted faster to the acoustic stimuli, and sex-related differences-found in controls-were not present in athletes. Our data also pointed out to substantial correlations between sensorimotor gating and physical conditioning parameters.

CONCLUSIONS

All in all, these data may point to physical conditioning-driven neural plasticity of brain sensorimotor gating circuits in charge of triggering involuntary movements to harness control and efficiency over reflexed muscle activity.

The effects of bending speed on the lumbo-pelvic kinematics and movement pattern during forward bending in people with and without low back pain

BACKGROUND

Impaired lumbo-pelvic movement in people with low back pain during bending task has been reported previously. However, the regional mobility and the pattern of the lumbo-pelvic movement were found to vary across studies. The inconsistency of the findings may partly be related to variations in the speed at which the task was executed. This study examined the effects of bending speeds on the kinematics and the coordination lumbo-pelvic movement during forward bending, and to compare the performance of individuals with and without low back pain.

METHODS

The angular displacement, velocity and acceleration of the lumbo-pelvic movement during the repeated forward bending executed at five selected speeds were acquired using the three dimensional motion tracking system in seventeen males with low back pain and eighteen males who were asymptomatic. The regional kinematics and the degree of coordination of the lumbo-pelvic movement during bending was compared and analysed between two groups.

RESULTS

Significantly compromised performance in velocity and acceleration of the lumbar spine and hip joint during bending task at various speed levels was shown in back pain group (p < 0.01). Both groups displayed a high degree of coordination of the lumbo-pelvic displacement during forward bending executed across the five levels of speed examined. Significant between-group difference was revealed in the coordination of the lumbo-pelvic velocity and acceleration (p < 0.01). Asymptomatic group moved with a progressively higher degree of lumbo-pelvic coordination for velocity and acceleration while the back pain group adopted a uniform lumbo-pelvic pattern across all the speed levels examined.

CONCLUSIONS

The present findings show that bending speed imposes different levels of demand on the kinematics and pattern of the lumbo-pelvic movement. The ability to regulate the lumbo-pelvic movement pattern during the bending task that executed at various speed levels was shown only in pain-free individuals but not in those with low back pain. Individuals with low back pain moved with a stereotyped strategy at their lumbar spine and hip joints. This specific aberrant lumbo-pelvic movement pattern may have a crucial role in the maintenance of the chronicity in back pain.

Acute Effects of Static vs. Ballistic Stretching on Strength and Muscular Fatigue Between Ballet Dancers and Resistance-Trained Women

Lima, CD, Brown, LE, Wong, MA, Leyva, WD, Pinto, RS, Cadore, EL, and Ruas, CV. Acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. J Strength Cond Res 30(11): 3220-3227, 2016-Stretching is used to increase joint range of motion, but the acute effects can decrease muscle strength. However, this may depend on the population or mode of stretching. The purpose of this study was to compare the acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. Fifteen resistance-trained women (age 23.8 ± 1.80 years, mass 67.47 ± 7.77 kg, height 168.30 ± 5.53 cm) and 12 ballet dancers (age 22.8 ± 3.04 years, mass 58.67 ± 5.65 kg, height 168.00 ± 7.69 cm) performed 5 days of testing. The first day was control (no stretching), whereas the other 4 days were static or ballistic stretching in a counterbalanced order. Range of motion, strength, and fatigue tests were also performed. Both groups demonstrated a significant decrease in hamstrings strength after static (102.71 ± 2.67 N·m) and ballistic stretching (99.49 ± 2.61 N·m) compared with control (113.059 ± 3.25 N·m), with no changes in quadriceps strength. For fatigue, only ballet dancers demonstrated a decrease from control (71.79 ± 4.88%) to ballistic (65.65 ± 8.19%), but no difference with static (65.01 ± 12.29%). These findings suggest that stretching decreases hamstrings strength similarly in ballet dancers and resistance-trained women, with no differences between modes of stretching. However, ballistic stretching only decreased muscular fatigue in ballet dancers, but not in resistance-trained women. Therefore, no stretching should be performed before strength performance. However, ballistic stretching may decrease acute muscular fatigue in ballet dancers.

Agreement Between Face-to-Face and Free Software Video Analysis for Assessing Hamstring Flexibility in Adolescents

The objective of this study was to determine the level of agreement between face-to-face hamstring flexibility measurements and free software video analysis in adolescents. Reduced hamstring flexibility is common in adolescents (75% of boys and 35% of girls aged 10). The length of the hamstring muscle has an important role in both the effectiveness and the efficiency of basic human movements, and reduced hamstring flexibility is related to various musculoskeletal conditions. There are various approaches to measuring hamstring flexibility with high reliability; the most commonly used approaches in the scientific literature are the sit-and-reach test, hip joint angle (HJA), and active knee extension. The assessment of hamstring flexibility using video analysis could help with adolescent flexibility follow-up. Fifty-four adolescents from a local school participated in a descriptive study of repeated measures using a crossover design. Active knee extension and HJA were measured with an inclinometer and were simultaneously recorded with a video camera. Each video was downloaded to a computer and subsequently analyzed using Kinovea 0.8.15, a free software application for movement analysis. All outcome measures showed reliability estimates with α > 0.90. The lowest reliability was obtained for HJA (α = 0.91). The preliminary findings support the use of a free software tool for assessing hamstring flexibility, offering health professionals a useful tool for adolescent flexibility follow-up.