Neck Strength Research Articles

Reliability of Repeated Isometric Neck Strength in Rugby Union Players Using a Load Cell Device.

Concussion is the most common injury in professional Rugby Union (RU) players, with increasing incidence and severity each year. Strengthening the neck is an intervention used to decrease concussion incidence and severity, which can only be proven effective if strength neck measures are reliable. We conducted a repeated-measures reliability study with 23 male RU players. Neck strength was assessed seated in a ‘make’ test fashion in flexion, extension, and bilateral-side flexion. Flexion-to-extension and left-to-right side ratios were also computed. Three testing sessions were undertaken over three consecutive weeks. Intrasession and intersession reliabilities were assessed using typical errors, coefficient of variations (CV), and intraclass correlation coefficients (ICC). Intrasession reliability demonstrated good-to-excellent relative (ICC > 0.75) and good absolute (CV ≤ 20%) reliability in all directions (ICC = 0.86–0.95, CV = 6.4–8.8%), whereas intersession reliability showed fair relative (ICC: 0.40 to 0.75) and acceptable absolute (CV ≤ 20%) reliability for mean and maximal values (ICC = 0.51–0.69, CV = 14.5–19.8%). Intrasession reliability for flexion-to-extension ratio was good (relative, ICC = 0.86) and acceptable (absolute, CV = 11.5%) and was fair (relative, ICC = 0.75) and acceptable (absolute, CV = 11.5%) for left-to-right ratio. Intersession ratios from mean and maximal values were fair (relative, ICC = 0.52–0.55) but not always acceptable (absolute, CV = 16.8–24%). Assessing isometric neck strength with a head harness and a cable with a load cell device seated in semi-professional RU players is feasible and demonstrates good-to-excellent intrasession and fair intersession reliability. We provide data from RU players to inform practice and assist standardisation of testing methods.

Neck strength and concussion prevalence in football and rugby athletes

ObjectivesTo determine the maximal isometric neck strength of male and female rugby and football (soccer) athletes, and to investigate the relationship between neck strength and sport played, sex, age, anthropometric measurements and concussion history. DesignCross-sectional observational study. MethodsIn total, 358 (70% male) healthy football and rugby playing adolescents and adults participated. Isometric neck strength and anthropometry measurements were collected, as well as completion of a sociodemographic survey. The mean (standard deviation) of all measurements for each age group was calculated and compared between sports and sexes, with correlation analyses performed to determine associations between all variables. ResultsIn general, rugby athletes had stronger neck musculature compared to football athletes, and males had stronger neck musculature compared to age-matched females, with these strength differences becoming increasingly significant with age (p < 0.05). The athletes with stronger neck muscles were older, taller, heavier, had higher bilateral grip strength and larger neck girth compared to those with weaker neck muscles (p < 0.05). Male rugby athletes who self-reported higher rates of a previous concussion had lower neck flexor/extensor strength ratio (p < 0.01). In 11–12-year-old male footballers, increased heading was associated with increased self-reported previous concussion (p < 0.01). ConclusionsThese normative neck strength data can form important reference values for rugby and football athletes from adolescence into adulthood. Male rugby athletes with a previous history of concussion demonstrated strength imbalances of their neck musculature (lower flexor/extensor ratio), with this finding having potentially important implications for training protocols and injury prevention initiatives.

Assessment of Neuromuscular and Psychological Function in People with Recurrent Neck Pain during a Period of Remission: Cross-Sectional and Longitudinal Analyses.

The aim of this study was to examine for the presence of differences in neuromuscular and psychological function in individuals with recurrent neck pain (RNP) or chronic neck pain (CNP) following a whiplash trauma compared to healthy controls. A secondary aim was to examine whether neuromuscular characteristics together with psychological features in people with RNP were predictive of future painful episodes. Multiple features were assessed including neck disability, kinesiophobia, quality of life, cervical kinematics, proprioception, activity of superficial neck flexor muscles, maximum neck flexion and extension strength, and perceived exertion during submaximal contractions. Overall, those with RNP (n = 22) and CNP (n = 8) presented with higher neck disability, greater kinesiophobia, lower quality of life, slower and irregular neck movements, and less neck strength compared to controls (n = 15). Prediction analysis in the RNP group revealed that a higher number of previous pain episodes within the last 12 months along with lower neck flexion strength were predictors of higher neck disability at a 6-month follow-up. This preliminary study shows that participants with RNP presented with some degree of altered neuromuscular features and poorer psychological function with respect to healthy controls and these features were similar to those with CNP. Neck flexor weakness was predictive of future neck disability.

Comparison of femoral neck geometric parameters between Chinese and Japanese females.

Femoral neck fracture is the most serious osteoporotic fractures that is responsible for high medical costs and high mortality. Femoral neck geometric parameters (FNGPs) are important parameters that reflect the geometrical characteristics of femoral neck, and are closely related to the strength of femoral neck and the risk of fragility fracture.There are differences in the incidence of femoral neck fractures among races. However, whether there is difference in FNGPs among races is unknown.Therefore, this study aims to compare the differences in FNGPs between Chinese and Japanese females. This study was a cross-sectional study, in which 3 859 healthy females aged 10-86 (45.7±17.1) years old were recruited from Changsha City of Hunan Province and surrounding areas. The weight and height were measured and recorded, and the body mass index (BMI) was calculated. A dual energy X-ray absorptiometry (DXA) bone densitometer was used to measure femoral neck projective bone area (BA) and bone mineral density (BMD). FNGPs were calculated using the BMD and BA, which included the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compression strength index (CSI). The data of FNGPs in Japanese females was collected from literature. These subjects were grouped by 10-year age. The mean and standard deviation of height, weight, BMI, femoral neck BMD, and FNGPs of each group were calculated. The model with the best goodness-of-fit was selected from various mathematical regression models to analyze the distribution trend and the best fitting curve of FNGPs with age. The differences in FNGPs between Chinese and Japanese females were analyzed by using age-corresponding mean fitting curve for paired t-test, and the relative change rates of FNGPs were compared. The mean values of FNGPs were significantly different among different years old healthy females (all P<0.01). The mean values of OD, CSA, CT, SM, and CSMI in femoral neck were high at 30 to 39 years old, and then they were gradually decreased with age. The CSI reached its peak at 20-29 years old, and it was decreased gradually after 30 years old. ED and BR were at a low level before 40 years old, they were gradually increased after 40 years old, and reached the maximum average value at 80-86 years old. The variations in FNGPs with age were fitted with the best goodness-of-fit by applying the cubic regression model and the determination coefficients of regression equations (R2: 0.062-0.404) were significant (all P<0.01). The distribution trend of FNGPs with age varied with the indices, among which CSA, CT, SM, CSMI and CSI were increased with age before 35 years old, and then they were decreased with age; BR was at a low level in the early stage, and then it was increased with age after about 40 years. There were significant differences in the fitting curves of FNGPs related to age between Chinese and Japanese females (all P<0.01). The fitting curves of OD, ED, BR and SM in Chinese females were significantly higher than those in Japanese females (all P<0.01), while those of CSA and CT in Chinese females were significantly lower than those in Japanese females (all P<0.01). Before the age of 50, the curves of CSMI and CSI of Chinese females were significantly higher than those of Japanese females (all P<0.01), while after the age of 60 the situation was reversed (all P<0.01). Except for SM and CSI, there were significant differences in the rate of OD, CSA, CT, ED, BR and CSMI with age (all P<0.01). By the age of 80 years old, the rates of change in OD, ED, and BR with the age in Chinese females were increased by 0.91%,3.94%, and 47.5%, respectively, while those in Japanese females were increased by 8.57%, 15.8% and 85.3%, respectively；the rates of change of CSA, CT, and CSMI with the age in Chinese females were declined 28.0%, 29.6%, and 25.2%, respectively, while those in Japanese females were declined 29.9%, 36.2%, and 10.9%, respectively. There were significant difference in the rates of change in FNGPs with the age between Chinese and Japanese females (all P<0.01). The study reveals the variation of FNGPs with age in Chinese, and confirms that there are racial differences in FNGPs between Chinese and Japanese females, which may be one of the important reasons for the difference in the incidence of femoral neck fracture between Chinese and Japanese females.

Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players

BackgroundConcussion is one of the highest burden injuries within professional Rugby Union (‘rugby’) and comes with a high health and financial cost to players and teams. Limited evidence exists as...

The value of mineral density and quality indicators of bone tissue in ensuring its strength in osteoporosis

The purpose of that investigation was to study the factors influencing the strength of femoral neck and its endurance to loads in osteoporosis. In experiment 24 samples of proximal femur obtained in autopsy from patients older than 60 years who died from different diseases without disturbance of bone metabolism were investigated. Mineral density of cortical and cancellous bones was assessed in standard zones using dual-energy x-ray absorptiometry (DEXA) and quantitative computed tomography (QCT). For the imitation of soft tissues the samples were placed in water and that allowed to compare the data obtained with norm measurement used for diagnosis of osteoporosis. Strength of femoral neck and its cortical layer as well as limit of elastic deformities, deformity value of femoral neck were evaluated in gradually increasing load. High correlation was showed between neck strength and BMD (r=0.86, p0.001). Osteoporotic qualitative state of bone and structural peculiarities of femoral neck influenced the bone strength independently of BMD value. The main role of cortical bone in providence the strength offemoral neck was confirmed in experiment.

Systematic review and meta-analysis of evaluation of selective cesarean section in postpartum pelvic floor function recovery under perineal ultrasound.

Different delivery modes can affect the early pelvic floor function of puerpera, but there are no reports on the systematic evaluation of the effects of selective cesarean section delivery (CSD) and vaginal delivery (VD) on the pelvic floor function of puerpera. We searched for clinical controlled studies on the evaluation of pelvic floor function and performance after CSD and VD, published between 1 January 2010 and 1 August 2021, in the databases of PubMed, Embase, The Cochrane Library, and Web of Science. Literature was screened according to the inclusion and exclusion criteria. The quality of trials included in the studies was evaluated using the Cochrane Working Manual (5.3). Meta-analysis of the extracted data from the eligible articles was performed using Review Manager 5.3 software. The heterogeneity was assessed by chi-square, and P<0.05 was considered statistically significant among groups. A total of 3,704 parturient women were included in 10 articles, including 1,072 cases in the CSD group and 2,632 cases in the VD group. Meta-analysis showed that pelvic floor muscle strength {mean difference (MD) [95% confidence interval (CI)]: -12.51 (-17.10 to -7.91); Z=5.34; P<0.00001} and bladder neck strength decreases in the CSD group [standardized mean difference (SMD) (95% CI): 1.01 (0.73 to 1.29); Z=7.08; P<0.00001] were higher than those in the VD group. In addition, the maximum urine flow [MD (95% CI): -6.86 (-9.32 to -4.39); Z=5.46; P<0.00001], bladder angle [MD (95% CI): -3.82 (-4.54 to -3.11); Z=10.46; P<0.00001], stress urinary incontinence (SUI) rate [relative risk (RR) (95% CI): 0.56 (0.35 to 0.88); Z=2.52; P=0.01], and pelvic floor organ prolapse rate [odds ratio (OR) (95% CI): 0.29 (0.09 to 0.89); Z=2.17; P=0.03] were lower than VD group, and the differences were significant (P<0.05). Selective CSD can reduce the injury of pelvic floor muscle during delivery to a certain extent, and reduce the incidence of SUI and pelvic floor organ prolapse in early puerpera; however, such impacts cannot be completely avoided.

Intermittent parathyroid hormone treatment affects the bone structural parameters and mechanical strength of the femoral neck after ovariectomy-induced osteoporosis in rats

BackgroundMenopause-induced decline in estrogen levels in women is a main factor leading to osteoporosis. The objective of this study was to investigate the effect of intermittent parathyroid hormone (PTH) on bone structural parameters of the femoral neck in ovariectomized rats, in addition to correlations of maximum fracture force.MethodsFifteen female Wister rats were divided into three groups: (1) control group; (2) ovariectomized (OVX) group; and (3) OVX + PTH group. All rats were then killed and the femurs extracted for microcomputed tomography scanning to measure volumetric bone mineral density (vBMD) and bone structural parameters of the femoral neck. Furthermore, the fracture forces of femoral neck were measured using a material testing system.ResultsCompared with the control and OVX + PTH groups, the OVX group had significantly lower aBMD, bone parameter, and mechanical strength values. A comparison between OVX and OVX + PTH groups indicated that PTH treatment increased several bone parameters. However, the OVX + PTH groups did not significantly differ with the control group with respect to the bone structural parameters, except for trabecular bone thickness of cancellous bone, which was greater. In addition, among the bone structural parameters, the CSA and BSI of cortical bone were significantly correlated with the maximum fracture force of the femoral neck, with correlations of, respectively, 0.682 (p = 0.005) and 0.700 (p = 0.004).ConclusionIntermittent PTH helped treat ovariectomy-induced osteoporosis of cancellous bone and cortical bone in the femoral necks of rats. The ability of the femoral neck to resist fracture was highly correlated with the two parameters, namely cross-sectional area (CSA) and bone strength index (= vBMD × CSA), of cortical bone in the femoral neck and was less correlated with aBMD or other bone structural parameters.

A suspected intermediate syndrome and intussusception following propoxur toxicity in a dog

AbstractAn 8‐month‐old, mixed breed dog was referred because of vomiting, generalised muscle tremors and miosis. A few hours before the presentation, the owners saw the dog eating something during the daily walk. The dog was initially treated with fluids, atropine, dexmedetomidine, maropitant and midazolam. Complete blood exams showed a marked reduction of cholinesterase activity. Blood toxicology tests revealed the presence of propoxur. Twenty‐four hours after the presentation, the dog developed a small intestinal intussusception. After an initial improvement, the dog developed weakness and respiratory difficulties. The neurological examination showed obtundation, severe generalised muscle weakness of neck and limbs, reduced flexor reflexes in the four limbs and a short and shallow respiratory pattern, suggesting suspected intermediate syndrome. The dog's neurologic conditions progressively improved, and he was discharged 5 days after presentation with only mild impairment of the neck strength.

Comparison of the effectiveness of a structured exercise program on nonspecific neck pain in string and woodwind players.

To investigate the effect of a structured exercise training program on pain, functional status, physical function and quality of life (QoL) in string and woodwind players with nonspecific cervical pain. This study had a prospective cohort design and conducted on 40 musicians (26 male, 14 female) aged between 18 and 65years with persistent nonspecific neck pain in the previous 3months. Forty musicians were assigned to either violin (n = 20, median age; 26.5year, height; 1.67m, body mass; 65kg, BMI; 23.04kg/m2) or ney group (n = 20, median age; 27.5year, height; 1.81m, body mass; 75kg, BMI; 23.35kg/m2) and followed the same structured exercise program (3days/per week for 8weeks). The primary outcome was neck pain intensity and assessed on a visual analog scale (VAS). Secondary outcomes; cervical range of motion (ROM) was measured using a goniometer, the jaw-to-sternum and jaw-to-wall distances were used for the assessment of cervical mobility, neck, shoulder and back muscles strength were assessed with a hand-held dynamometer, the Northwick Park Neck Pain and Short Form 36 (SF-36) questionnaires were also used. Normality of data distribution was checked using the Kolmogorov-Smirnov test. For evaluating the training effectiveness on outcome measures, Mann-Whitney U and Wilcoxon test were used compare pre-test and post-test values with/within groups, respectively. The primary outcome (pain intensity) was lowered %33 in both groups. However, the mean change was found similar (median mean changes; -2 for both groups) (p > 0.05). The secondary outcomes; cervical mobility, cervical flexion ROM, disability and muscle strength of the left middle trapezius, left hand grip, anterior and middle parts of the right deltoid, and cervical flexors also significantly improved in both groups (p < 0.05). Only the mean changes of right serratus anterior, middle trapezius and cervical flexor muscles were higher in violin group than ney group (p < 0.05). There was no significant difference in the cervical extension, right rotation, left rotation, right lateral flexion and left lateral flexion after the treatment in both groups (p > 0.05). There was no significant difference between the groups after the exercise program in terms of pain, mobility, range of motion and SF-36 subdomains (p > 0.05). Specific exercise program had similar positive effects on pain, cervical mobility, cervical fexion ROM and disability in string and woodwind players. Although several muscles showed similar improvements in strength, some muscle groups recovered differently. Physical needs specific to the instrument and performance should be taken into account when prescribing exercises to musicians having the same problem, but playing different instruments.

Relationships Between Pulmonary Function and Composite Indices of Femoral Neck Strength in Korean Men (KNHANES IV).

BackgroundDespite the close relationship between osteoporosis and chronic pulmonary diseases, few studies have evaluated relationships between pulmonary functions and bone quality. We investigated associations between pulmonary function test results and femoral neck strength indices (SIs) in Korean men.MethodsThis population-based, cross-sectional study was conducted using data from the Korea National Health and Nutrition Examination Survey IV on 936 men aged ≥ 19 years. Pulmonary functions (forced vital capacity [FVC] and forced expiratory volume in one second [FEV1]) were measured using a dry rolling seal spirometer. Femoral neck SIs, relative to load, were calculated by hip dual-energy X-ray absorptiometry for compression strength index (CSI), bending strength index (BSI), and impact strength index (ISI).ResultsThe 443 (47.3%) of the 936 men were current smokers. FVC, FVC percentage with respect to the expected normal value, FEV1, and FEV1 percentage with respect to the expected normal value (FEV1p) were positively associated with CSI and BSI after adjusting for confounders, including smoking history (β = 0.003–0.223, P = 0.005–0.036). FEV1 and FEV1p were positively associated with ISI (β = 0.000–0.014, P = 0.010–0.025). Of components of femoral neck SIs, bone mineral density was correlated with FEV1 and FEV1p (β = 0.001–0.037, P = 0.017–0.019). After adjusting for all confounders, all femoral neck SIs increased with FVC quintiles (P for trends = 0.001–0.012), and CSI and BSI increased with FEV1 quintiles (P for trends = 0.034–0.043).ConclusionReduced pulmonary function was correlated with reduced femoral neck strength, even after adjusting for smoking history in Korean men. Femoral neck SIs might be useful tools for evaluating bone health in men with reduced pulmonary function.

Application of intelligent X-ray image analysis in risk assessment of osteoporotic fracture of femoral neck in the elderly.

The paper focuses on establishing a risk assessment model of femoral neck osteoporotic fracture (FNOF) in the elderly population and improving the screening efficiency and accuracy of such diseases in specific populations. In literature research, the main risk factors of femoral neck osteoporosis (FNOP) in the elderly were studied and analyzed; the femur region of interest (ROI) and the hard bone edge segmentation model were selected from the X-ray digital image by using the image depth learning method. On this basis, the femoral trabecular score and femoral neck strength (FNS) in the set region were selected as the main evaluation elements, and the quantitative analysis method was established; an X-ray image processing method was applied to the feasibility study of FNOP and compared with dual-energy X-ray absorptiometry measurements of bone mineral density; Finally, the main risk factors of FNOP were selected and the prediction model of FNOP in the elderly population was established based on medical image processing, machine learning model construction and other methods. Some FNOP health records were selected as test samples for comparative analysis with traditional manual evaluation methods. The paper shows the risk assessment model of FNOF in the elderly population, which is feasible in testing. Among them, the artificial neural network model had a better accuracy (95.83%) and recall rate (100.00%), and the support vector machine prediction model had high specificity (62.50%). With the help of a machine learning method to establish the risk assessment model of FNOF for the elderly, one can provide decision support for the fracture risk assessment of the elderly and remind the clinic to give targeted interventions for the above high-risk groups in order to reduce the fracture risk.

Sex Differences in Neck Strength Force and Activation Patterns in Collegiate Contact Sport.

The purpose of this study was to assess changes in cervical musculature throughout contact-heavy collegiate ice hockey practices during a regular season of NCAA Division III ice hockey teams. In this cross-sectional study, 36 (male n = 13; female n = 23) ice hockey players participated. Data were collected over 3 testing sessions (baseline; pre-practice; post-practice). Neck circumference, neck length, head-neck segment length, isometric strength and electromyography (EMG) activity for flexion and extension were assessed. Assessments were completed approximately 1h before a contact-heavy practice and 15 min after practice. For sternocleidomastoid (SCM) muscles, males had significantly greater peak force and greater time to peak force versus females. For both left and right SCMs, both sexes had significantly greater peak EMG activity pre-practice versus baseline, and right (dominant side) SCM time to peak EMG activity was decreased post-practice compared to pre-practice. There were no significant differences for EMG activity of the upper trapezius musculature, over time or between sexes. Sex differences observed in SCM force and activation patterns of the dominant side SCM may contribute to head stabilization during head impacts. Our study is the first investigation to report changes in cervical muscle strength in men's and women's ice hockey players in the practical setting.

The effect of giving verbal feedback during neck stabilisation exercise as an addition to physical therapy in patients with chronic neck pain: A randomised controlled trial

Objectives To study the addition of feedback-guided neck strength home exercise to physical therapy as an enhanced rehabilitation programme in the treatment of patients with chronic neck pain. Design A prospective randomised controlled trial. Setting Rehabilitation department of an academic hospital. Subjects Patients with chronic neck pain. Interventions The patients in both groups received supervised physical therapy sessions 3 times a week for 12 weeks. Patients in Group A (N = 38) used the neck strengthening exerciser device for 20 min daily at home for 6 weeks and patients in Group B (N = 20) performed 20 min of daily regular neck exercise at home for 6 weeks. Outcome measures Neck disability index, pain visual analogue scale, active range of motion of the neck, Patient Global Assessment and patient evaluation of treatment effect. All subjects were assessed at baseline as well as at 6- and 12-week follow-ups. Results At the 6-week follow-up, Group A exhibited significantly greater improvements (P < 0.05) in pain Visual Analogue Scale (Group A: 2.97 ± 1.57; Group B: 4.20 ± 1.82), neck disability index (Group A: 13.95 ± 8.07; Group B: 20.07 ± 9.14) and active cervical extension (Group A: 65.26 ± 12.76; Group B: 51.45 ± 11.78). At 12-week follow-up, Group A also exhibited significantly greater active cervical extension (Group A: 67.74 ± 11.94; Group B: 53.85 ± 14.09; P < 0.05). Conclusion Adding neck strengthening exerciser home training to physical therapy was demonstrated to be more effective than physical therapy alone for patients with chronic neck pain.

An Accessible, 16-Week Neck Strength Training Program Improves Head Kinematics Following Chest Perturbation in Young Soccer Athletes.

Neck size and strength may be associated with head kinematics and concussion risks. However, there is a paucity of research examining neck strengthening and head kinematics in youths. In addition, neck training is likely lacking in youth sport due to a perceived inadequacy of equipment or time. Examine neck training effects with minimal equipment on neck strength and head kinematics following chest perturbations in youth athletes. Single-group, pretest-posttest case series. Athlete training center. Twenty-five (14 men and 11 women) youth soccer athletes (9.8 [1.5]y). Sixteen weeks of twice-weekly neck-focused resistance training utilizing bands, body weight, and manual resistance. Head kinematics (angular range of motion, peak anterior-posterior linear acceleration, and peak resultant linear acceleration) were measured by an inertial motion unit fixed to the apex of the head during torso perturbations. Neck-flexion and extension strength were assessed using weights placed on the forehead and a plate-loaded neck harness, respectively. Neck length and circumference were measured via measuring tape. Neck extension (increase in median values for all: +4.5kg, +100%, P < .001; females: +4.5kg, +100%, P = .002; males: +2.2kg, +36%, P = .003) and flexion (all: +3.6kg, +114%, P < .001; females: +3.6kg, +114%, P = .004; males: +3.6kg, +114%, P = .001) strength increased following the intervention. Men and women both experienced reduced perturbation-induced head pitch (all: -84%, P < .001). However, peak resultant linear acceleration decreased in the female (-53%, P = .004), but not male (-31%, P = 1.0) subgroup. Preintervention peak resultant linear acceleration and extension strength (R2 = .21, P = .033) were the closest-to-significance associations between head kinematics and strength. Young athletes can improve neck strength and reduce perturbation-induced head kinematics following a 16-week neck strengthening program. However, further research is needed to determine the effect of improved strength and head stabilization on concussion injury rates.

Associations of neck muscle strength and cervical spine\xa0mobility with future neck pain and disability: a prospective 16-year study

BackgroundNeck pain has been associated with weaker neck muscle strength and decreased cervical spine range of motion. However, whether neck muscle strength or cervical spine mobility predict later neck disability has not been demonstrated. In this 16-year prospective study, we investigated whether neck muscle strength and cervical spine mobility are associated with future neck pain and related disability in women pain-free at baseline.MethodsMaximal isometric neck muscle strength and passive range of motion (PROM) of the cervical spine of 220 women (mean age 40, standard deviation (SD) 12 years) were measured at baseline between 2000 and 2002. We conducted a postal survey 16 years later to determine whether any subjects had experienced neck pain and related disability. Linear regression analysis adjusted for age and body mass index was used to determine to what extent baseline neck strength and PROM values were associated with future neck pain and related disability assessed using the Neck Disability Index (NDI).ResultsThe regression analysis Beta coefficient remained below 0.1 for all the neck strength and PROM values, indicating no association between neck pain and related disability. Of the 149 (68%) responders, mean NDI was lowest (3.3, SD 3.8) in participants who had experienced no neck pain (n = 50), second lowest (7.7, SD 7.1) in those who had experienced occasional neck pain (n = 94), and highest (19.6, SD 22.0) in those who had experienced chronic neck pain (n = 5).ConclusionsThis 16-year prospective study found no evidence for an association between either neck muscle strength or mobility and the occurrence in later life of neck pain and disability. Therefore, screening healthy subjects for weaker neck muscle strength or poorer cervical spine mobility cannot be recommended for preventive purposes.

Sex differences in neck strength and head impact kinematics in university rugby union players

ABSTRACT Globally, over three million women participate in rugby union, yet injury prevention and training strategies are predominantly based on androcentric data. These strategies may have limited generalisability to females, given the cervical spine is more susceptible to whiplash and less adept at resisting inertial loading. A total of 53 university rugby union players (25 female, 28 male, 20.7 ± 1.8 years) had their isometric neck strength measured. Bespoke instrumented mouthguards were used to record the magnitude of head impact events in six female and seven male competitive matches. Mean female maximal isometric neck strength was 47% lower than male. Independent samples Mann–Whitney U tests showed no significant differences for peak linear head acceleration (female: median 11.7 g, IQR 7.9 g; male: median 12.5 g, IQR 7.0 g p=.23) or peak rotational head acceleration (female: median 800.2 rad·s−2, IQR 677.7 rad·s−2; male: median 849.4 rad·s−2, IQR 479.8 rad·s−2; p=.76), despite the mean male body mass being 24% greater than female. Coded video analysis revealed substantial differences in head-impact mechanisms; uncontrolled whiplash dominated >50% of all recorded female impact events and <0.5% in males. Direct head-to-ground impacts comprised 26.1% of female and 9.7% of male impacts, with whiplash occurring in 78.0% and 0.5%, respectively. Overall, the data provided in this study do not support the generalisation of male-derived training and injury-prevention data to female rugby athletes. These results suggest a considerable research effort is required to identify specific weakness of female rugby players and derive appropriate training, injury prevention and return to play protocols. Highlights Video analysis revealed substantial differences in head-impact mechanisms, with uncontrolled whiplash dominating >50% of all recorded female impact events but rarely in males. Isometric neck strength was 47% lower in female players than males. Direct head-to-ground impacts accounted for 26.1% and 9.7% of female and male impacts, with whiplash occurring in 78.0% and 0.5%, respectively.

The Effect of Four Months of Core Stability Training on Femoral Bone Mineral Density and Lower Extremity Muscles Strength in Postmenopausal Women

Background: Osteoporosis is a skeletal disease associated with a gradual decline of bone density, as well as a characteristic reduction of bone rigidity and an increased risk of fractures. This study aimed to investigate the effects of four months of core stability training on the bone mineral density (BMD) of the femur neck and lower extremity muscles strength in postmenopausal women. Methods: This study was an interventional semi-experimental one designed with a pre-test/post-test approach. Overall, 30 postmenopausal women aged 48 to 58 years were purposefully selected and then randomly divided into two groups of core stability exercise (weight= 70.73 ± 12.57 Kg) and control (weight= 77.86 ± 7.19 Kg) groups. The participants of the core stability group performed the exercise protocol three times a week for four months. These exercises consisted of five levels, and based on the gradual progress principle, their intensity was gradually increased over the four months during the study. The participants of the control group did not perform any exercise during the study. The BMD of the dominant femur neck was measured by a Dexa device, and the flexor and external rotator strength of the hip was measured by a manual dynamometer. Data analysis was performed applying paired and independent-sample t-test in SPSS 23 software. The significant level was set at 0.05. Results: The results of paired samples t-test showed that the BMD of the femur neck significantly increased in the core stability group (Pvalue=0.001) and significantly decreased in the control group (Pvalue=0.045) at the post-test compared to the pre-test. Also in intra-group comparison, the flexor and external rotator strength of the hip significantly were increased in the core stability group (Pvalue=0.001 and 0.001, respectively). While there was not such a significant change in the control group. On the other hand, based on the results of the independent samples t-test, the femur neck BMD (Pvalue=0.007) and the flexor and external rotator strength of the hip (Pvalue=0.001 and 0.001, respectively) significantly increased in the core stability compared to the control group. Conclusions: According to the results, it seems that core stability exercises can be suggested to postmenopausal women as an effective strategy for osteogenic bone behavior and reducing the risk of osteoporosis. Keywords : Core stability training, Femur bone mineral density, Lower extremity muscles strength, Postmenopausal women

An examination of two different approaches for the study of femoral neck fracture: Towards a more relevant rodent model.

Femoral neck fractures are a massive personal and health programme burden. Methods to study femoral neck strength, across its combined trabecular and cortical components are therefore essential. Rodent ovariectomy-induced osteoporosis models are commonly coupled with ex vivo 3-/4-point bending methods to measure changes in femoral cortical diaphysis. The loading direction used to assess these properties are often non-physiologic and, moreover, these ovariectomy models are linked to marked weight gain that can influence the biomechanical properties. Herein, we explore whether more physiological axial ex vivo loading protocols applied to femoral neck samples of ovariectomised (OVX) rodents provide anatomically-relevant models for the assessment of strength. We examine the use of mouse and rat femurs, loaded in constrained and unconstrained configuration, respectively, and explore whether weight-correction increases their utility. Accordingly, the mid-shaft of the proximal half of femurs from OVX and sham-operated (Sham) mice was methacrylate-anchored and the head loaded parallel to the diaphysis (constrained). Alternatively, femurs from OVX and Sham rats were isolated intact and axially-loaded through hip and knee joint articular surfaces (unconstrained). Yield displacement, stiffness, maximum load and resilience were measured and fracture pattern classified; effects of body weight-correction via a linear regression method or simple division were assessed. Our data reveal significant deficiencies in biomechanical properties in OVX mouse femurs loaded in constrained configuration, only after weight-correction by linear regression. In addition, evaluation of rat femur biomechanics in unconstrained loading demonstrated greater variation and that weight-correction by simple division improved scope to reveal significant OVX impact. We conclude that greater femoral neck fracture susceptibility can indeed be measured in OVX rodents as long as multiple biomechanical parameters are reported, care is taken in choosing the method for assessing load-bearing strength and weight-correction applied. These studies advance the establishment of more relevant rodent models for the study of femoral neck fracture.

An isometric neck strengthening program does not improve neck strength in elite women's football-code athletes: A randomised controlled trial

ObjectivesThe purpose of this study was to investigate the effectiveness of an isometric neck strengthening program to improve isometric neck strength in elite women's football-code athletes. DesignRandomised controlled trial. MethodsElite female soccer (n = 10) and Australian football (n = 30) players were randomised into either a control (n = 20) or experimental (n = 20) group for a 12-week intervention study during their respective seasons. While both groups undertook their prescribed strength and conditioning programs, the experimental group also performed isometric neck strengthening exercises three times per week prior to training. Isometric neck strength of the extensors, flexors, lateral flexors, and rotators were assessed pre, mid (Week 7), and post (Week 13) intervention with a hand-held dynamometer during early to mid-competition season. A mixed design analysis of variance was performed for statistical analysis. ResultsNo significant group-by-time interactions in isometric neck strength were observed. All strength variables displayed a significant change over time throughout the 12-week period (p < 0.05). No significant between group differences in isometric neck strength variables were observed except for lateral left flexion (F(1, 38) =5.064, p = 0.030, η2p = 0.117). ConclusionsThe addition of isometric neck strengthening exercises did not improve neck strength beyond a standard strength and conditioning program for elite women's football-code athletes. While this specific program may not improve neck strength in elite women's football-code athletes, further investigation is needed to determine whether sport-specific neck strength exercises may improve neck strength or if lower-level competition athletes may still benefit from an isometric neck strengthening program.