Intrarater Reliability of Neck Strength Measurement of Rugby Union Players Using a Handheld Dynamometer

Comparison of two different manual techniques for an exercise program for the management of chronic neck pain: A randomized clinical trial study

BACKGROUND

Both spinal manipulation (SM) and Integrated Neuromuscular Inhibition Technique (INIT) have a positive effect in individuals with chronic neck pain (CNP), especially when they are combined with therapeutic exercise (TE). However, it has not been determined which of the above combinations is more effective in patients with CNP.

OBJECTIVE

To compare the efficacy of two different manual techniques (SM and INIT), when combined with the same TE program in the management of CNP.

METHODS

Eighty women with CNP, allocated into four groups of 20 persons each. The first group followed a 10-week TE program, the second TE and INIT, the third TE and SM, and the fourth was the control group. The Visual Analogue Scale (VAS) for pain, Neck Disability Index (NDI), Pressure Pain Threshold (PPT) of the neck muscles, neck active Range of Motion (ROM), Maximum Isometric Strength (MIS) of the neck muscles, craniocervical flexion test (CCFT) and SF-36 questionnaire scores were evaluated before, during and after the treatment period, with a six-month follow-up.

RESULTS

There was between groups differences between the three intervention groups and the control group (p< 05), with the positive effects being maintained until the six-month follow-up. However, this improvement occurred earlier in the "TE + INIT" and "TE + SM" groups than in the "TE" group. Differences between the "TE + INIT" and the "TE + SM" groups were noticed only in the neck muscles PPT values, in which the "TE + INIT" group showed greater improvement. Furthermore, some non-statistically significant indications for further improvement of "TE + SM" were noted in the left lateral flexion ROM.

CONCLUSION

The addition of INIT as well as SM in the same TE program can further increase the beneficial effect of exercise in women with CNP. In most measurements both combinations seem to be equally effective. However, INIT improved more local muscle tenderness, whereas SM aided more in the neck lateral flexion ROM.

Intra and Inter-Rater Reliability of a Novel Isometric Test of Neck Strength

There is no single, universally accepted method of measuring isometric neck strength to inform exercise prescription and injury risk prediction. This study aimed to establish the inter- and intra-rater reliability of a commercially available fixed frame dynamometer in measuring peak isometric neck strength. A convenience sample of male (n = 16) and female (n = 20) university students performed maximal isometric contractions for flexion (Flex), extension (Ext), left- (LSF) and right-side flexion (RSF) in a quadruped position over three sessions. The intra-rater reliability results were good-to-excellent for both males (ICC = 0.83−0.90) and females (ICC = 0.86−0.94) and acceptable (CV < 15%) across all directions for both males and females. The inter-rater reliability results were excellent (ICC = 0.96−0.97) and acceptable (CV < 11.1%) across all directions. Findings demonstrated a significant effect for sex (p ≤ 0.05): males were stronger in all four directions, and a significant effect for direction (p ≤ 0.05): Ext tested stronger (193 N) than Flex (176 N), LSF (130 N) and RSF (125 N). The findings show that the VALD fixed frame dynamometer can reliably assess isometric neck strength and can provides reference values for healthy males and females.

Neck Strength Evaluated With Fixed and Portable Dynamometers in Asymptomatic Individuals: Correlation, Concurrent Validity, and Agreement

OBJECTIVE

The purpose of this study was to assess the correlation, concurrent validity, and agreement between the isometric cervical force measurements obtained with fixed and portable dynamometers in asymptomatic individuals.

METHODS

Fifty asymptomatic individuals performed 3 maximal isometric contractions for flexion, extension, and lateral flexion of the cervical spine using fixed and portable dynamometers. The correlation and concurrent validity for the measurements of the portable and fixed dynamometers were analyzed using Spearman's correlation coefficient and the intraclass correlation coefficient (ICC), respectively. The agreement between the force values of the portable and fixed dynamometers was measured using the Bland-Altman method.

RESULTS

Isometric cervical force measurements obtained with the fixed dynamometer and portable dynamometer showed a moderately to highly significant correlation for flexion (r_s = 0.74), extension (r_s = 0.82), right lateral flexion (r_s = 0.74), and left lateral flexion (r_s = 0.68). The concurrent validity was moderate to good for all measurements (ICC_2,3 = 0.67-0.80). The fixed and portable dynamometers did not agree, with a significant mean difference between the methods of 2.8 kgf (95% confidence interval [CI], 2.1-3.4 kgf) for cervical flexion, 5.3 kgf (95% CI, 4.2-6.4 kgf) for extension, and 9.1 kgf (95% CI, 0.4-2.1 kgf) for left lateral flexion. The limits of agreement were broad for all movements, with errors that varied between 61% and 77% of the mean force obtained with the fixed dynamometer.

CONCLUSION

The neck strength measurements obtained with the fixed and portable dynamometers demonstrated high to moderate correlation and had moderate to good comparability for asymptomatic participants. However, they did not agree in that the 2 methods did not provide equivalent measurements, and, therefore, based on these findings, the same equipment should always be used when reassessing an individual.

Reliability and difference in neck extensor muscles strength measured by a portable dynamometer in individuals with and without chronic neck pain

OBJECTIVE

There are limited reports about the reliability of measuring neck extensor muscle strength using a portable dynamometer in neck pain patients. The aims of the current study were 1) to investigate intra- and inter-rater reliability of neck extensor isometric strength measurement using a portable dynamometer in patients with chronic nonspecific neck pain (CNSNP) and 2) to compare neck extensor isometric strength in participants with and without CNSNP.

METHODS

Guidelines for Reporting Reliability and Agreement Studies (GRRAS) were followed. Two examiners received a 15-minute training before enrollment. Inter-rater reliability was assessed with a 10-minute interval between measurements, and intra-rater reliability was assessed with a 10-day interval. Three trials were assessed and examiners were blind to the strength values (in Newtons) from other sessions of 20 individuals with CNSNP (mean±SD= 37.9 ± 9.8y; Neck Disability Index 29.2 ± 7.4%) and 20 individuals with other musculoskeletal disorders (mean ± SD = 32.8 ± 46.2y).

RESULTS

Intra-rater reliability was excellent with intraclass correlation coefficient (ICC)(3,1) of 0.95 (CI:0.90-0.97) and inter-rater reliability was good to excellent with ICC(2,1) of 0.88 (CI:0.77-0.94) in CNSNP. No significant difference of neck extensor strength was found between CNSNP (93.27N±31.94) and Individuals without CNSNP (111.43N±40.11) (p > 0.05).

CONCLUSION

A portable dynamometer is a reliable tool for measuring maximal isometric neck extension strength in individuals with CNSNP. Slightly but no significant differences of neck extensor strength values between individuals with and without CNSNP. Future studies are needed to assess the generalizability of the findings in patients with other muscle deconditioning.

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.

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

BACKGROUND

Concussion 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 to the existence of modifiable intrinsic risk factors for concussion, leaving athletes and clinicians with few options when developing prevention strategies.

OBJECTIVE

To investigate whether neck strength is significantly associated with concussion incidence in professional male rugby players.

METHODS

225 rugby players were assessed for neck strength at three time points throughout the 2018/2019 season using a method of isometric contraction. Associations with clinically diagnosed concussion injuries are presented as incidence rate ratios (IRRs) with 95% CIs.

RESULTS

Thirty concussions occurred in 29 players during the study period; a rate of 13.7 concussions per 1000 hours played. Greater neck strength was observed at mid and end of season time points versus preseason across the study population. There was a significant association between extension strength and concussion; a 10% increase for extension strength was associated with a 13% reduction in concussion rate (adjusted IRR (95% CI) 0.87 (0.78 to 0.98). No other significant associations were observed between concussion incidence and any other unique neck strength range or composite score.

CONCLUSION

Higher neck extension strength is associated with lower concussion rates in male rugby players. Neck strength is a modifiable intrinsic risk factor for concussion and may be an important component of a strength and conditioning regime.

Neck strength in Rugby Union players: a systematic review of the literature

The incidence and severity of concussion injuries are increasing every year. Scientific evidence indicates that neck strength and girth could play a role in preventing head and neck injuries, or at least mitigating their severity. We aimed to examine the scientific literature addressing neck strength in Rugby Union with a focus on the potential role of neck strength on injury incidence, neck assessment protocols, neck strength measures, and neck strengthening exercises.We conducted a systematic search of the literature in January 2021 to locate published peer-reviewed articles from PubMed, SPORTDiscus^TM, Web of Science®, and Scopus® e-databases. Overall, senior elite male players were stronger than younger-aged players. Forwards were stronger in extension than any other directions assessed, and were generally stronger and possessed larger necks and greater cross-sectional areas when compared to backs. Implementation of isometric exercise routines in professional players was reported to improve neck strength in all directions. There were no studies evaluating the incidence of concussion and neck strength or neck strengthening strategies in Rugby Union. Strengthening the neck continues to be one of the targeted modifiable risk factors with respect to limiting the severity and temporal effects of head injuries in Rugby Union, despite limited evidence regarding direct associations between neck strength and concussion.

The concurrent validity and intrarater reliability of a hand-held dynamometer for the assessment of neck strength in semi-professional rugby union players

OBJECTIVES

The main objective of this study was to determine the concurrent validity between a hand-held (HHD) and mounted hand-held dynamometer (MHHD) for assessing isometric neck strength.

DESIGN

Observational design.

SETTING

Semiprofessional rugby club.

PARTICIPANTS

Nineteen semi-professional rugby players (age = 26 ± 5 years, stature = 186.5 ± 6.5 cm, body mass = 98.7 ± 12.8 kg).

MAIN OUTCOME MEASURES

Concurrent validity (limits of agreement, correlation) between HHD and MHHD, the intrarater reliability (intra-class correlation, ICC) and comparison between playing positions.

RESULTS

Absolute peak and mean peak force were systematically lower when using the HHD compared to MHHD, with the mean bias ranging from -1.8 to -3.8 kgf (P < 0.05). Differences were not evident for flexion when applying the correction equations (-0.5 to 2.1 kgf, P > 0.05) but remained for extension. Correlations between methods were large-to-very large; the ICCs for both methods were good (ICC = 0.72-0.89), with no difference between positions (P < 0.05).

CONCLUSION

The concurrent validity of HHD was considered acceptable when compared to the MHHD and the correction equation applied. Both methods are reliable and useful for assessing neck strength in rugby players, though, caution is needed when determining strength during neck extension.

Concurrent Validity and Reliability of a Low-Cost Dynamometer to Assess Maximal Isometric Strength in Neck Movements

OBJECTIVE

This study aimed to evaluate the concurrent validity and reliability of a low-cost digital dynamometer to assess maximal isometric strength in neck movements.

METHODS

Twelve recreationally active participants (6 women, 6 men; age: 24.1 ± 3.4 years; height: 1.71 ± 0.06 m; weight: 64.6 ± 11.7 kg) performed neck flexion, extension, and lateral flexion, and maximal isometric strength was simultaneously measured using an isokinetic dynamometer (gold standard) and a digital dynamometer to evaluate the concurrent validity of the latter. One week later, all the participants repeated 3 trials of each neck movement (3 minutes apart) registered only with the digital dynamometer. The first and second trial were guided by tester 1 and the third trial was guided by tester 2.

RESULTS

The concurrent validity of the digital dynamometer showed a nearly perfect correlation between both devices (r > 0.986, P < .001), with Bland-Altman plots showing absolute agreement. Intertester and intratester reliability were nearly perfect for all neck movements (intraclass correlation coefficient > 0.86).

CONCLUSION

The low-cost digital dynamometer showed valid and reliable measurements of maximal isometric strength in neck movements.

Reliability and Validity of Clinical Tests for Measuring Strength or Endurance of Cervical Muscles: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the reliability and validity of clinical tests for measuring cervical muscle strength or endurance in participants with and without neck pain.

DATA SOURCE

Systematic review and meta-analysis on reliability and validity. Literature search was conducted on January 28, 2020, using 5 databases: MEDLINE, Cumulative Index to Nursing and Allied Health, EMBASE, SPORTDiscus, and Scopus.

STUDY SELECTION

We included studies that investigated the reliability or validity of clinical tests for measuring cervical muscle strength or endurance in participants with nonspecific chronic neck pain, with or without irradiation, or healthy participants. We included only those that were viable for daily practice and of low cost.

DATA EXTRACTION

Data were extracted as follows: (1) author and year of publication, (2) demographic values and health condition, (3) reported clinical tests, (4) inclusion and exclusion criteria, (5) description of test, (6) interrater reliability, and (7) intrarater reliability. For validity studies we also extracted the (8) reference method and (9) validity estimates.

DATA SYNTHESIS

Methodological quality was assessed with the Quality Appraisal of Diagnostic Reliability and the Guidelines for Reporting Reliability and Agreement Studies. Data on reliability and validity were extracted from included articles and then analyzed.

RESULTS

Thirty-one studies were included. Cervical flexor and extensor endurance test, craniocervical flexion test (CCFT), AND cervical muscle strength using a handheld dynamometer (HHD) showed moderate to good intra- and interrater reliability (intraclass correlation coefficients ranging from 0.64-0.90). Concurrent validity was measured by only 2 studies, which do not provide adequate evidence for a recommendation.

CONCLUSIONS

The cervical flexor and extensor endurance tests, CCFT, and HHD for measuring cervical strength presented an acceptable interrater and intrarater reliability.

Reliability and validity of measurements of cervical retraction strength obtained with a hand-held dynamometer

Objectives: The purpose of this study was to describe the reliability and validity of measurements of cervical retraction strength obtained with a hand held dynamometer (HHD) from healthy adults. Background: Impaired neck muscle strength is related to neck pain, abnormal posture, and various cervical pathologies. While sophisticated devices to objectively measure neck strength exist, many are not practicable in typical orthopedic practices or have questionable validity and reliability. Methods: Forty participants were included in the analysis of neck strength using isometric testing with an HHD fixed in a cradle on a table top. The highest neck retraction force recorded in Newtons (N) for each participant, was used for data analysis. Results: Both intratester and intertester reliability were excellent as judged by intraclass correlation coefficients (ICCs) (.885 - .974) and minimal detectable change (MDC) (21.1 to 47.6 N). Validity was confirmed on the basis of expected gender and age differences (ie, men were stronger than women and younger participants were stronger than older participants). Conclusion: Fixed HHD is a reliable and valid tool for measuring isometric neck retraction strength in ostensibly healthy adults. Its value in the assessment of individuals with neck pathology awaits further examination.

Relationship between cervical muscle morphology evaluated by MRI, cervical muscle strength and functional outcomes in patients with degenerative cervical myelopathy

BACKGROUND

Cervical muscle alterations have been reported in patients with chronic neck pain, but the assessment of muscle morphology and strength has been overlooked in patients with degenerative cervical myelopathy (DCM).

OBJECTIVES

This study aimed to investigate the relationship between cervical muscle degenerative changes observed on MRI, muscle strength and symptoms severity in patients diagnosed with DCM.

DESIGN

Observational study.

METHODS

Cervical muscle measurements of total cross-sectional area (CSA), functional CSA (fat free area, FCSA) and ratio of FCSA/CSA (e.g. fatty infiltration) were obtained from T2-weighted axial MR images from C2-C3 to C6-C7 in 20 patients. Muscle strength was assessed manually using a microFET2 dynamometer. The association between cervical muscle morphology parameters, muscle strength, symptoms severity and functional status was investigated.

RESULTS

Greater mean CSA and FCSA was associated with greater overall muscle strength. The mean FCSA explained 37%, 76%, 39%, 20% and 65% of the total variance in flexion, extension, right-side bending, left-side bending and overall muscle strength, respectively. The mean ratio of FCSA/CSA was not significantly associated with cervical muscle strength in any direction. However, greater FCSA/CSA ratio (e.g. less fatty infiltration) was associated with lower disability score (p = 0.02, R² = 0.20).

CONCLUSIONS

Cervical muscle lean muscle mass was positively associated with cervical muscle strength in patients with DCM. Moreover, greater fatty infiltration in the cervical extensor muscles was associated with lower functional score. Such findings suggest that clinicians should pay greater attention to cervical muscle morphology and function in patients with DCM.

A Comparison of Various Cervical Muscle Strength Testing Methods Using a Handheld Dynamometer

BACKGROUND:

Cervical muscle strength, proposed as a modifiable risk factor in concussions, can be assessed using various methods. The purpose of this study was to compare the reliability and force outputs of 3 methods that use handheld dynamometry (HHD) for assessing cervical muscle strength.

HYPOTHESIS:

All 3 testing methods are reliable, and force outputs are significantly different between methods.

STUDY DESIGN:

Repeated-measures reliability.

LEVEL OF EVIDENCE:

Level 5.

METHODS:

The study used a convenience sample of 30 participants. HHD "make tests" for cervical extension, flexion, and right and left side bending were performed using lying push tests, sitting push tests, and sitting pull tests. A sole examiner performed all tests. Two testing sessions were conducted 1 week apart. Analysis included intraclass correlation coefficients (ICCs), repeated-measures analyses of variance (α = 0.05) with post hoc Bonferroni tests, and minimal detectable change (MDC) calculations.

RESULTS:

All testing methods were reliable; the lying push test had the greatest point estimate values (ICC, 0.89-0.95). Significant differences in force were found between the 3 testing methods. The MDC was most sensitive for the lying push method.

CONCLUSION:

Of the 3 cervical muscle testing methods investigated, the lying position with a push test had the largest ICC according to the point estimate and the most sensitive MDC. Force values between the 3 methods were significantly different, which suggests that consistent testing methods should be used.

CLINICAL RELEVANCE:

Results from this study support the clinical use of an HHD "make test" in a lying position for assessing cervical muscle strength. The test is reliable and more sensitive to change compared with tests in a seated position.

Test-retest reliability of a handheld dynamometer for measurement of isometric cervical muscle strength

BACKGROUND

There is a lack of test-retest reliability studies of measurements of cervical muscle strength, taking into account gender and possible learning effects.

OBJECTIVE

To investigate test-retest reliability of measurement of maximal isometric cervical muscle strength by handheld dynamometry.

METHODS

Thirty women (age 20-58 years) and 28 men (age 20-60 years) participated in the study. Maximal isometric strength (neck flexion, neck extension, and right/left lateral flexion) was measured on three separate days at least five days apart by one evaluator.

RESULTS

Intra-rater consistency tended to improve from day 1-2 measurements to day 2-3 measurements in both women and men. In women, the intra-class correlation coefficients (ICC) for day 2 to day 3 measurements were 0.91 (95% confidence interval [CI], 0.82-0.95) for neck flexion, 0.88 (95% CI, 0.76-0.94) for neck extension, 0.84 (95% CI, 0.68-0.92) for right lateral flexion, and 0.89 (95% CI, 0.78-0.95) for left lateral flexion. The corresponding ICCs among men were 0.86 (95% CI, 0.72-0.93) for neck flexion, 0.93 (95% CI, 0.85-0.97) for neck extension, 0.82 (95% CI, 0.65-0.91) for right lateral flexion and 0.73 (95% CI, 0.50-0.87) for left lateral flexion.

CONCLUSION

This study describes a reliable and easy-to-administer test for assessing maximal isometric cervical muscle strength.

Functional limitations and associated psychological factors in military personnel with chronic nonspecific neck pain with higher levels of kinesiophobia

BACKGROUND

Neck pain is one of the largest health problems in the military sector.

OBJECTIVE

To assess differences in the strength and endurance of the cervical muscles between military personnel with chronic nonspecific neck pain (CNSNP) with higher level of kinesiophobia (CNSNP-K) and individuals with lower levels of kinesiophobia (CNSNP-NK).

METHODS

We used kinesiophobia as a classification method: (1) CNSNP-K and (2) CNSNP-NK. The variables measured were endurance and strength of cervical muscles; range of motion (ROM), disability, pain intensity and psychological factors.

RESULTS

Eighty-three military personnel (26 CNSNP-K; 20 CNSNP-NK and 37 asymptomatic). Statistically significant differences in endurance and ROM were only found between the CNSNP-K group and the control group. In strength and disability differences were revealed between both symptomatic groups and the control group [CNSNP-K vs. control (flex-ext p <  0.001); CNSNP-NK vs. control (flex p = 0.003) and (ext p <  0.001)]. For psychological variables, the CNSNP-K group showed differences compared with the CNSNP-NK (pain catastrophizing, p = 0.007; anxiety and depression, p <  0.001) and with the asymptomatic group (pain catastrophizing, p = 0.008; anxiety and depression, p <  0.001).

CONCLUSIONS

Military personnel with CNSNP-K have functional limitations and associated psychosocial factors compared with asymptomatic subjects, and showed greater associated psychological factors than CNSNP-NK group. Military personnel with CNSNP-NK only showed decreased strength with respect to those who were asymptomatic.

Intrarater and Inter-rater Reliability of Maximal Voluntary Neck Muscle Strength Assessment Using a Handheld Dynamometer in Women With Headache and Healthy Women

OBJECTIVE

This study aimed to determine the inter-rater and intrarater reliability, agreement, and minimal detectable change (MDC) of the neck muscle strength test using a handheld dynamometer in healthy women and women with headaches.

METHODS

Neck muscle strength in maximal voluntary contraction was measured using the Lafayette Manual Muscle Testing attached to a nonelastic belt in 25 women with migraines and in 25 healthy women. Three repetitions of flexion, extension, and lateral flexion were performed. The tests were performed by 2 examiners on the same day, with a 10-minute interval, and by 1 examiner, with a 1-week interval. The reliability was verified by the intraclass correlation coefficient, the agreement determined by standard error measurement, and the MDC calculated.

RESULTS

The protocol exhibited moderate to excellent intrarater and inter-rater reliabilities in both groups (intraclass correlation coefficientrange, 0.53-0.90). The standard error measurement ranged from 0.43 to 1.81 and the MDC from 1.49 up to 4.61.

CONCLUSION

Quantification of neck muscle strength using the handheld dynamometer with an attached nonelastic belt exhibited moderate to excellent intra- and inter-rater reliability in women with and without migraines. Moreover, the standard error measurement and MDC were proven to be useful in the interpretation of data and in guiding clinical decisions.

Effects of neck strength training on isometric neck strength in rugby union players

OBJECTIVE

To investigate the effectiveness of a neck strengthening program on the isometric neck strength profile of male rugby union players.

DESIGN

Controlled laboratory study.

SETTING

Professional rugby union club.

PARTICIPANTS

Fifteen professional and 10 semiprofessional rugby union players.

INTERVENTIONS

The 15 professional players undertook a 5-week neck strengthening intervention, which was performed twice per week, whereas the 10 semiprofessional players acted as the control group.

MAIN OUTCOME MEASURES

Isometric strength of the neck musculature was tested using a hand-held dynamometer, for flexion (F), extension (E), left-side flexion (LSF), and right-side flexion (RSF). Preintervention and postintervention evaluations were undertaken.

RESULTS

No significant between-group differences in isometric neck strength were noted preintervention. A significant main effect for time was observed (P < 0.05), whereby the intervention group increased isometric neck strength in all planes after the 5-week intervention (F preintervention = 334.45 ± 39.31 N vs F postintervention 396.05 ± 75.55 N; E preintervention = 606.19 ± 97.34 vs E postintervention = 733.88 ± 127.16 N; LSF preintervention = 555.56 ± 88.34 N vs LSF postintervention = 657.14 ± 122.99 N; RSF preintervention = 570.00 ± 106.53 N vs RSF postintervention = 668.00 ± 142.18 N). No significant improvement in neck strength was observed for control group participants.

CONCLUSIONS

The results of the present study indicate that a 5-week neck strengthening program improves isometric neck strength in rugby union players, which may have implications for injury prevention, screening, and rehabilitation.

CLINICAL RELEVANCE

The strengthening program described in the present study may facilitate rehabilitation specialists in the development of neck injury prevention, screening, and rehabilitation protocols.