Isometric Muscle Endurance Research Articles

Impact of short-term functional training program on lower-body isometric muscle endurance in cricket players

Impact of short-term functional training program on lower-body isometric muscle endurance in cricket players

A Profile of Isometric Cervical Strength in Elite Professional Male Rugby Players.

OBJECTIVES: To (1) provide position-specific normative data for isometric cervical muscle strength and endurance in professional, male rugby players and (2) assess the relationship between age, height, weight, and playing position with cervical muscle strength and endurance. DESIGN: Cross-sectional study. METHODS: Professional rugby players completed peak isometric cervical strength testing followed by a test of cervical muscle endurance. Descriptive statistics for continuous variables with strength normalized to body weight were performed. Multiple linear regression was used to estimate associations between strength measurements. RESULTS: In total, 136 players participated including front-row forwards (27%), other forwards (28%), and backs (45%). Front-row forwards had significantly greater peak isometric cervical muscle strength than other position groups, with backs having the lowest strength. Extension produced the highest force for all 3 position groups (429 N ± 104 N), whereas flexion produced the least (275 N ± 65 N). Age was associated with increased isometric cervical muscle strength. There was a statistically significant relationship between peak flexion strength and flexion endurance (P = .003). The average time for the endurance tests were 55.7 (±17.1) seconds and 52.9 (±20.1) seconds for extension and flexion, respectively. Other forwards had lower cervical extension muscle endurance than backs and front-row forwards. CONCLUSIONS: Normative values for peak and endurance isometric strength in professional rugby players illustrate significant differences between playing position. Consider age, body weight, and intraindividual variability when interpreting cervical strength and endurance results. J Orthop Sports Phys Ther 2024;54(3):1-8. Epub 29 January 2024. doi:10.2519/jospt.2024.11830.

A Prospective Cohort Study on Risk Factors for Cervico-Thoracic Pain in Military Aircrew.

BACKGROUND: Military aircrew frequently report cervico-thoracic pain and injury. The relationship between risk factors and future pain episodes is, however, uncertain. The aim of this study was to identify risk factors for cervico-thoracic pain and to determine the 1-yr cumulative incidence of such pain.METHODS: A total of 47 Swedish aircrew (fighter and helicopter pilots and rear crew) without pain in the cervico-thoracic region were surveyed about work-related and personal factors and pain prevalence using the Musculoskeletal Screening Protocol questionnaire. They also performed tests of movement control, active cervical range of motion, and isometric neck muscle strength and endurance. Aircrew were followed for a year with questionnaires. Logistic regressions were used to identify potential risk factors for future cervico-thoracic pain.RESULTS: Previous cervico-thoracic pain (OR: 22.39, CI: 1.79-280.63), lower cervical flexion range of motion (OR: 0.78, CI: 0.64-0.96), and lower neck flexor muscular endurance (OR: 0.91, CI: 0.83-0.99) were identified as risk factors for reporting cervico-thoracic pain. At follow-up, 23.4% (CI: 13.6-37.2) had reported cervico-thoracic pain during the 12-mo follow-up period.DISCUSSION: The Musculoskeletal Screening Protocol can identify risk factors for cervico-thoracic pain. The link between cervico-thoracic pain and previous pain, as well as lower performance of neck range of motion and muscular endurance, highlights the need for primary and secondary preventive action. The findings from this study can facilitate the development of such pain prevention programs for aircrew.Tegern M, Aasa U, Larsson H. A prospective cohort study on risk factors for cervico-thoracic pain in military aircrew. Aerosp Med Hum Perform. 2023; 94(7):500-507.

Acute Effect of L-Citrulline Supplementation on Resistance Exercise Performance and Muscle Oxygenation in Recreationally Resistance Trained Men and Women.

L-citrulline serves as a nitric oxide precursor with the potential to increase blood flow and improve resistance exercise performance, yet more research is needed to examine its ergogenic potential. To examine the effect of L-citrulline supplementation on resistance exercise performance, muscle oxygenation, and the subjective perception of effort, energy, focus, fatigue, and muscle pump, eighteen resistance-trained men (n = 11) and women (n = 7) (21.4 ± 1.8 years; 172.3 ± 7.5 cm; 76.9 ± 10.8 kg) were randomly assigned for supplementation with 8 g of L-citrulline (CIT) or a placebo (PL) in a cross-over fashion one hour prior to testing. Participants completed an isometric mid-thigh pull test (IMTP), a ballistic bench press protocol [two sets of two repetitions at 75% 1-repetition maximum (1 RM) with maximum ballistic intent], and a strength-endurance bench press protocol [five repetition-maximum sets at 75% 1RM]. Barbell velocity and power were measured via a linear position transducer during the ballistic protocol, while the repetitions completed, volume load and muscle oxygenation were quantified during the strength-endurance protocol. Subjective measures were assessed at the baseline and immediately pre- and post-exercise. Repeated measures of the analysis of variance and Bayesian equivalents revealed no significant interactions, providing evidence favoring the null hypothesis (BF10 < 1) for IMTP (PL 497.5 ± 133.6 vs. CIT 492.5 ± 129.4 N), barbell velocity, and power, and repetitions completed (PL 36.7 ± 7.2 vs. CIT 36.9 ± 8.1 repetitions). There were also no significant interactions for muscle oxygenation parameters or subjective measures except perceived fatigue. Women reported greater fatigue across all time points compared to men (~1.88 au, p = 0.045, BF10 = 0.2). The results indicate that a single 8 g dose of L-citrulline did not enhance isometric force production, muscle endurance, or muscle oxygenation parameters during the protocol implemented in this study.

Remote and local ischemic preconditioning increases isometric strength and muscular endurance in recrea-tional trained individuals

The aim of the present study was to verify the acute effect of remote and local IPC application before isometric strength, lumbar and lower limbs manual grip, and upper limbs and trunk muscle endurance tests in recreationally trained individuals. The volunteers were 22 men (age: 26.2 ± 6.9 years, weight: 83.4 ± 11.6 kg, height: 175.4 ± 5.8 cm, BMI: 27.1 ± 3.5 kg.m-2) recreationally trained (4.6 ± 3.3 years) in resistance exercise (RE) that performed three visits on non-consecutive days (three to seven days apart). This was a crossover and randomized study. In the first visit, the Informed Consent Form (ICF) was signed, according to the Declaration of Helsinki, and the PAR-Q was completed. Immediately after, anthropometrics was assessed, followed by familiarization with the tests. At the second and third visits, the volunteers were randomly assigning to the following experimental protocols: a) IPC protocol with 220 mmHg + isometric strength and muscular endurance tests (IPC); or b) control protocol (CON) isometric strength and muscular endurance tests. Isometric handgrip strength was significantly higher in IPC compared to CON (61.59±10.18 vs. 58.95±10.84, 4.47Δ%, p=0.01). Lumbar isometric strength was significantly higher in IPC compared to CON (165.36±22.56 vs. 156.77±22.81, 5.48Δ%, p= 0.01) and lower limbs isometric strength was significantly higher in IPC compared to CON (163.09±22.92 vs. 154.86±21.55, 5.31Δ%, p=0.01). Push-up repetitions were significantly higher in IPC compared to CON (43±12.80 vs. 38.91±13.03,10.51Δ%, p=0.01). The trunk flexion repetitions were significantly higher in the IPC compared to the CON (46.05±13.28 vs. 40.23±11.18, 14.46Δ%, p=0.01). In conclusion, local IPC significantly increased upper limb isometric strength and muscle endurance compared to the control protocol. Remotely, IPC significantly increased lower limb isometric strength, lumbar and trunk flexion muscular endurance compared to the control protocol. Keywords: Ischemic preconditioning, Isometric strength, Muscular endurance

Acute Effect of Different Warm-up Methods on Isometric Muscle Endurance of the Finger Flexors and Climbing Performance in Sport Climbers

PURPOSE The purpose of this study was to investigate whether foam roller, preexhaustion, and static stretching had any effect on isometric muscular endurance of the finger flexors and climbing performance in sport climbers. METHODS Nine sport climbers who were able to perform at a climbing difficulty of 5.11d, were included in this study. Warm-up exercise consisted of myofascial release, pre-exhaustion exercises, and static stretching. Grip and back strengths were measured for muscular strength, and isometric muscular endurance of the finger flexors was measured as the time spent hanging on each hold according to the angle of the elbow joint. Repeated measures of ANOVA were performed to confirm the difference in treatment, and a significant difference between groups was confirmed by contrast test. RESULTS Myofascial release, pre-exhaustion, and static stretching before climbing did not affect muscle strength. However, the static stretching exercise significantly decreased isometric muscle endurance of the finger flexor at 90° open hold, and the pre-exhaustion exercise significantly decreased the hanging time at 180° crimp and slope grips. There was no effect on climbing performance according to the type of warm-up exercise. CONCLUSIONS Our findings suggested that various warm-up exercises did not directly affect muscle strength, muscular endurance, and climbing performance in sport climbers. Thus, we suggest that future research on complex warm-up exercises considering climbing postures should be conducted.

Lumbopelvic sagittal standing posture associations with anthropometry, physical activity levels and trunk muscle endurance in healthy adults.

Background:Various factors, inherited and acquired, are associated with habitual spinal postures.Objective:The purpose of this study was to identify the relationships between trunk muscle endurance, anthropometry and physical activity/inactivity and the sagittal standing lumbopelvic posture in pain-free young participants.Methods:In this study, 112 healthy young adults (66 females), with median (IQR) age of 20 years (18.2–22 years), without low back pain, injury or trauma were included. Lumbar curve (LC) and sacral slope (SS) angles were measured in standing with a mobile phone application (iHandy level). Anthropometric, physical activity/inactivity levels (leisure-time sport involvement and sitting hours/day) and abdominal (plank prone bridge test) and paraspinal (Sorensen test) isometric muscle endurance measures were collected.Results:LC and SS angles correlated significantly (, ). Statistically significant differences for both LC () and SS () angles were identified between the male and female participants. A significant negative correlation was identified between the abdominal endurance time and LC (, ); however, the power of this result (56%) was not sufficiently high. The correlation between abdominal endurance and SS was non-significant (, ). In addition, no significant associations were identified between either of the sagittal lumbopelvic angles (LC–SS) in standing and the participants’ body mass index (BMI), paraspinal endurance, leisure-time sport involvement or sitting hours/day.Conclusion:The potential role of preventive exercise in controlling lumbar lordosis via enhancement of the abdominal muscle endurance characteristics requires further confirmation. A subsequent study, performed in a larger population of more diverse occupational involvement and leisure-time physical activity levels, is proposed.

등척성 체간 운동이 젊은 성인의 근지구력과 균형능력에 미치는 영향

This study aims to identify the effects of an isometric trunk exercise program on muscle endurance and balance ability in young adults. Fourteen young adults volunteered to participate in this study. Isometric muscle endurance tests (trunk curl in supine, hyperextension of trunk in prone, and arm-supporting side bridge) and one-leg standing test were used to measure muscle endurance and balance of subjects. Isometric trunk exercises were performed for 30 minutes, twice per week for 6 weeks (a total of 12 sessions), including upper and lower abdominal drawing, abdominal bracing, posterior pelvic tilting, supine bridge exercise, and alternating raising of limbs in quadruped position. After the intervention, significant improvements were found for all items of muscle endurance and balance (p<.05). These findings suggest that an isometric trunk exercise program might be favorably used to enhance muscle endurance if the trunk and balance in young adults. Further studies need to support our findings.

Acute Effects of a Brief Physical Exercise Intervention on Somatosensory Perception, Lumbar Strength, and Flexibility in Patients with Nonspecific Chronic Low-Back Pain.

BackgroundEvidence-based clinical guidelines consider physical exercise one of the best nonpharmacological interventions for low-back pain (LBP), but it is necessary to clarify the exercise-induced hypoalgesia effect of different modalities of exercise in chronic pain populations.PurposeThis study focused on exploring acute changes in tactile and pressure-pain perception and lumbar strength and flexibility in patients with nonspecific chronic LBP (NSCLBP) after performing one of three 20-minute physical exercise modalities.MethodsA total of 81 patients with NSCLBP were pseudorandomly distributed into three groups of 20-minute physical exercise — 1) aerobic (n=21, mean age 42±9.72 years, nine men), 2) stretching (n=21, mean age 40±11.37 years, ten men), and 3) strengthening (n=20, mean age 35.80±11.56 years, ten men) — and 4) a control group (n=19, mean age 38.64±10.24 years, eight men), and completed self-reported questionnaires during the same period. Tactile and pressure-pain thresholds and isometric lumbar muscle endurance and flexibility were assessed before and after this brief exercise-based intervention.ResultsAll groups were comparable in terms of sociodemographic and clinical data, cardiovascular capacity, and self-reported data onphysical disability, mood, motivation, psychological response to stimulus properties of physical exercise, and physical activity enjoyment. Our analyses revealed higher tactile sensitivity (p<0.001) and pressure-pain thresholds (p<0.001) at the forefinger than other body locations. We also found lower pain sensitivity (p=0.010) and pressure pain–intensity ratings (p=0.001) and higher lumbar flexibility (p<0.001) after intervention. After calculation of absolute pre–post differences, higher tactile sensitivity was observed at the gluteus medius muscle than the erector spinal muscle only after aerobic intervention (p=0.046).ConclusionThese results add some evidence about different modalities of exercise-induced hypoalgesia in NSCLBP. However, the fact that we also found improvements in the control group limits our conclusions.

BLOOD PRESSURE IS THE KEY PHYSIOLOGICAL INDICATOR OF HIKING PERFORMANCE IN LASER SAILORS

Purpose: The aim of this study is to examine the physiological basis of hiking performance, which is the determinant of performance in laser class sailors. Method: This research was conducted with 16 male athletes between the ages of 15-25 who actively attend laser class races held by Turkish Sailing Federation. The participants were classified as High Performance (HP) and Low Performance (LP) according to their race results and the number of attended international races (as a member of national team). Physical and anthropometric measurements, performance measurements (isometric muscle endurance test during hiking position in simulator) of these volunteers were obtained. During the simulator test, heart rate per minute, systolic and diastolic blood pressure values were monitored and recorded as well. Mann Whitney U test was used to analyze the differences statistically among the groups. Result: Statistically significant differences were observed in the parameters of body mass index, isometric muscle endurance(time to exhaustion),diastolic blood pressure and heart rate during and after the test, and recovery heart rate in the FP and DP groups (p<0.05). Conclusion: The findings of this study show that changes in the blood pressure parameters during the Hiking performance are an important indicator of performance. Monitoring blood pressure in the hiking position in competition-based training can contribute to the determination of the sailor's performance level and training needs. also shows that extensive researches with higher numbers of athletes are needed for future studies.

Comparison of muscle strength and bone mineral density in healthy postmenopausal women. A cross-sectional population study

In this cross-sectional population study with 78 healthy 0.5-5 years postmenopausal, 49-55 year old females a significant simple linear correlation between lumbar spine LII-LIV bone mineral density and adjacent back extensor and flexor isometric muscle strength was found. With the stepwise multiple linear regression analyses the most significant predictors for lumbar spine LII-LIV and femoral neck bone mineral density were weight (partial R2) (R2 = 0.197, p = 0.0001; R2 = 0.157, p = 0.0009) and age (R2 = 0.056, p = 0.0205; R2 = 0.036, p = 0.0708). Height and isometric muscle strength and endurance of muscles were not significant predictors. Weight and age were the most significant predictors also for isometric muscle strength. The mobility of spine, body fat content and anaerobic threshold had no correlation on bone mineral density.

Perioperative Blood Flow Restriction Rehabilitation in Patients Undergoing ACL Reconstruction: A Systematic Review.

Background:Low-load blood flow restriction (BFR) training has attracted attention as a potentially effective method of perioperative clinical rehabilitation for patients undergoing orthopaedic procedures.Purpose:To (1) compare the effectiveness of low-load BFR training in conjunction with a standard rehabilitation protocol, pre- and postoperatively, and non-BFR interventions in patients undergoing anterior cruciate ligament reconstruction (ACLR) and (2) evaluate protocols for implementing BFR perioperatively for patients undergoing ACLR.Study Design:Systematic review; Level of evidence, 2.Methods:A systematic review of the 3 medical literature databases was conducted to identify all level 1 and 2 clinical trials published since 1990 on BFR in patients undergoing ACLR. Patient demographics from included studies were pooled. Outcome data were documented, including muscle strength and size, and perceived pain and exertion. A descriptive analysis of outcomes from BFR and non-BFR interventions was performed.Results:A total of 6 studies (154 patients; 66.2% male; mean ± SD age, 24.2 ± 3.68 years) were included. Of these, 2 studies examined low-load BFR as a preoperative intervention, 1 of which observed a significant increase in muscle isometric endurance (P = .014), surface electromyography of the vastus medialis (P < .001), and muscle blood flow to the vastus lateralis at final follow-up (P < .001) as compared with patients undergoing sham BFR. Four studies investigated low-load BFR as a postoperative intervention, and they observed significant benefits in muscle hypertrophy, as measured by cross-sectional area; strength, as measured by extensor torque; and subjective outcomes, as measured by subjective knee pain during session, over traditional low-load resistance training (all P < .05). BFR occlusion periods ranged from 3 to 5 minutes, with rest periods ranging from 45 seconds to 3 minutes.Conclusion:This systematic review found evidence on the topic of BFR rehabilitation after ACLR to be sparse and heterogeneous likely because of the relatively recent onset of its popularity. While a few authors have demonstrated the potential strength and hypertrophy benefits of perioperative BFR, future investigations with standardized outcomes, long-term follow-up, and more robust sample sizes are required to draw more definitive conclusions.

Core Stability and Symmetry of Youth Female Volleyball Players: A Pilot Study on Anthropometric and Physiological Correlates

The aim of the present study was to examine the variation in core stability and symmetry of youth female volleyball players by age, and its relationship with anthropometric characteristics, the 30 s Wingate anaerobic test (WAnT), and the 30 s Bosco test. Female volleyball players (n = 24, age 13.9 ± 1.9 years, mean ± standard deviation) performed a series of anthropometric, core stability tests (isometric muscle endurance of torso flexors, extensors, and right and left lateral bridge), WAnT (peak power, mean power, Pmean, and fatigue index, FI) and Bosco test (Pmean). Flexors-to-extensors ratio and right-to-left lateral bridge ratio were also calculated. Participants were grouped into younger (n = 12, 12.3 ± 1.2 years) or older than 14 years (n = 12, 15.4 ± 1.0 years), and into normal (flexors-to-extensors ratio &lt; 1; n = 17) or abnormal flexors-to-extensors ratio (≥1; n = 7). The older age group was heavier (+11.3 kg, mean difference; 95% CI, 2.0, 20.6) and with higher body mass index (+2.8 kg m−2; 95% CI, 0.4, 5.1) than the younger age group. The group with abnormal flexors/extensors had larger flexors muscle endurance (+77.4 s; 95% CI, 41.8, 113.0) and higher flexors/extensors ratio (+0.85; 95% CI, 0.61, 1.10) than the normal group. Body fat percentage (BF) correlated moderately-to-largely with flexors (r = −0.44, p = 0.033), extensors (r = −0.51, p = 0.011), and left lateral bridge (r = −0.45, p = 0.027); WAnT Pmean moderately-to-largely with right (r = 0.46, p = 0.027) and left lateral bridge (r = 0.55, p = 0.006); FI moderately-to-largely with right (r = −0.45, p = 0.031) and left lateral bridge (r = −0.67, p &lt; 0.001), and right/left ratio (r = 0.42, p = 0.046); Bosco Pmean correlated moderately-to-largely with right (r = 0.48, p = 0.020) and left lateral bridge (r = 0.67, p = 0.001). A stepwise regression analysis indicated FI and BF as the most frequent predictors of core stability. The findings of the present study suggested that increased core stability was related to decreased BF and increased anaerobic capacity. A potential misbalance between torso flexors and extensors might be attributed to bidirectional variations (either high or low scores) of flexors muscle endurance rather than decreased extensors muscle endurance.

Isometric Sore Muscle Endurance in Healthy Active and Non-active Working Age Populations

Isometric Sore Muscle Endurance in Healthy Active and Non-active Working Age Populations

CANINE-ASSISTED THERAPY AND THE IMPROVEMENT OF PHYSICAL CHARACTERISTICS IN DISABLED CHILDREN: A PILOT STUDY

Materials and methods. Three groups of mentally disabled children of different age participated in dog-assisted therapy sessions twice per week for two months. Motor skills evaluation was based on the Bruininks-Oseretsky motor skills evaluation test (short version). Isometric torso muscle endurance tests were based on Ito, McIntosh and McGill. The ability to focus and memorise exercises and the ability to understand and perform them was also evaluated. Results. Movement perception and performance, as well as ability to focus and memorise the movement sequel improved after canine-assisted exercise sessions. The most significant changes in performance were observed in the torso muscle static endurance test, push-ups, fine motor skills, and coordination (p&lt;0.001). Conclusion. Dogs can be successfully used as motivation for the performance of various task or to lower psychological tension and anxiety during exercise sessions. It is hoped that the results of this study will be used for the development of formal dog-assisted therapy guidelines for use in physical therapy with mentally disabled children.

Kronik boyun ağrısında bakış yönü tanıma egzersizlerinin ağrı şiddeti, eklem hareket açıklığı ve izometrik kas enduransına etkisi

Purpose: The aim of this study was to evaluate the effect of the Gaze Direction Recognition Task on pain intensity, range of motion and isometric muscle endurance in patients with chronic neck pain. Materials and Methods: A total of 40 participants (32 female, 8 male) aged between 29-54 years (mean age: 44.98 ± 6.38) participated voluntarily in our study. Participants were randomly divided in two groups (GDRT Group and Control Group). Both groups underwent combined physiotherapy program. Both groups received in total 15 sessions of therapy during 3 weeks, 5 days per week. The GDRT Group has additionally underwent 15 sessions of Gaze Direction Recognition Tasks. Pain Intensity (Visual Analog Scale), range of motion (universal goniometer), isometric muscle endurance (craniocervical test) and the Gaze direction recognition task assessments were repeated before, after and 6 weeks after the treatment programme.Results: After therapy, improvement was observed in terms of pain intensity, flexion, extension, lateral flexion, left rotation range of motion and isometric muscle endurance in both groups (p&amp;lt;0.05). Statistically significant differences were recorded in terms of pain intensity, flexion, lateral flexion of both direction, right rotation range of motion, muscle strength and gaze direction recognition task scores between two groups (p&amp;lt;0.05).Conclusion: The Gaze Direction Recognition Tasks given additionally to the combined physiotherapy program has increased the efficiency of the treatment.

Trunk muscle endurance in Chinese adults.

Previous studies in non-Chinese populations have found a relationship between performance on isometric trunk muscle endurance tests and low back pain (LBP). However, the relationship between trunk muscle endurance and LBP in Chinese populations has received little attention and age-referenced data have not been reported. Evaluate the relationship between age-referenced isometric trunk muscle endurance values and LBP in a Chinese cohort. One hundred and eighty-eight participants (20-59-years) performed four timed-endurance tests (Biering-Sørensen, plank, left/right side bridge) in random order. Participants with a history of LBP completed an Oswestry Disability Index (ODI) and pain scale. Holding-times for the four tests were summed and receiver operating characteristic (ROC) curve analysis was performed to differentiate participants with and without LBP. Data were grouped by age. Analysis revealed similar endurance values to those reported in non-Chinese populations, except longer holding times were recorded in the 50-59yr Chinese cohort. Pain scores were positively correlated with ODI scores. ROC curve analysis showed that the area under the curve was 0.723 and optimal cut-off was 288 sec (sensitivity and specificity both 0.75). This study is the first to describe trunk muscle endurance reference data in Chinese people. Individuals with a summed endurance time of < 288 seconds appear more likely to suffer LBP.

Isometric muscle fatigue of the paravertebral and upper extremity muscles after whiplash injury.

BACKGROUNDWhiplash-associated disorders (WAD) result from injury of neck structures that most often occur during traffic accidents as a result of rapid acceleration-deceleration. The dominant symptoms manifest in the musculoskeletal system and include increased fatigue. Because of the frequency of whiplash injuries, a simple, cheap and useful diagnostic tool is needed to differentiate whiplash injury from healthy patients or those faking symptoms.OBJECTIVESTo determine muscle fatigue in patients with whiplash injury in six body positions.DESIGNAnalytical cross-sectional study.SETTINGEmergency center, university hospital.PATIENTS AND METHODSWe studied patients with whiplash injury from vehicular traffic accidents who presented to the emergency center within 6 hours of sustaining the injury. We determined whiplash injury grade according to the Quebec Task Force (QTF) classification and measured isometric muscle endurance in six different body positions. Control subjects for each patient were matched by age, gender and anthropomorphic characteristics. Cut-off values were determined to distinguish patients with whiplash injury from controls and for determination of injury grade.MAIN OUTCOME MEASURE(S)QTF grade, time to muscle fatigue in seconds.RESULTSFrom September 2013 to September 2016, we enrolled 75 patients with whiplash injury and 75 matching control subjects. In all six positions, the patients with whiplash injury felt muscle fatigue faster than equivalent controls (P<.05) and the time to onset of muscle fatigue decreased with increasing injury grades in all six positions. Assignment to the patient or control group and to injury grade could be predicted with more than 90% accuracy on the basis of time to muscle fatigue. The most efficient position was the highest injury grade, by which 99.9% of the patients were accurately categorized. Isometric muscle endurance correlated with whiplash injury grade in all six positions (P<.01).CONCLUSIONUnder clinical conditions, muscle endurance and the appearance of isometric muscle fatigue during testing can be a useful indicator of whiplash injury and grade.LIMITATIONSThe size of the sample was small. An objective parameter such as electromyography is needed to confirm isometric muscle fatigue.

Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study.

BackgroundLow back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes.ObjectivesThe aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP.MethodsIn total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study).ResultsThe mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables.ConclusionsThe data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players.

The relationship between isometric trunk muscle endurance and physical activity related energy expenditure in healthy young adults.

Despite the popularity of core stabilization, there is limited evidence as to the relationship between performance on tests of isometric trunk muscle endurance and physical activity levels in adults. To investigate the relationship between isometric trunk muscle endurance and physical activity related energy expenditure in healthy young adults. A total of 51 participants (24 female) participated in the study. Median age and body mass index were; 22 years (Min-max: 18-26 years) and 21.8 kg/m2 (Min-Max: 18.59-28.98 kg/m2), respectively. Participants completed the International Physical Activity Questionnaire. Isometric trunk muscle endurance was assessed with holding times of isometric trunk flexor, extensor, and lateral side bridge tests. Collected data were summarized based on median and interquartile ranges. The Spearman's correlation test was used to ascertain the relationship between isometric trunk muscle endurance and physical activity related energy expenditure. There were no gender differences in holding times of the trunk flexor and trunk extensor endurance tests (p> 0.05). Males showed higher endurance scores for side bridge test than females (p< 0.001). No difference was found in physical activity related energy expenditure between males and females. No correlation was observed between isometric trunk muscle endurance and physical activity related energy expenditure for either females or males (p> 0.05). According to our findings, trunk muscle endurance is not related to physical activity related energy expenditure in healthy young adults.