A novel device to assess hip strength: Concurrent validity and normative values in male athletes

Acute neuromuscular and perceptual responses to U-18 English Premier League academy football match play

We examined the sensitivity and time-course of recovery of neuromuscular and perceptual player monitoring measures to U-18 English Premier League academy football match play. Eighteen players performed maximal posterior chain, hip adductor and abductor isometric strength tests, countermovement jumps (CMJ) and provided self-report wellbeing scores around eight competitive league home games: 1 day before (MD-1), pre-match (MD-PRE), post-match (MD-POST) and two (MD+2) and three (MD+3) days post-match. A permutational multivariate analysis of variance and post hoc univariate analyses of variance were used to examine match-induced responses to monitoring variables. Between MD-1 and MD-POST, we observed small to moderate reductions to the adductor and abductor peak force and maximal impulse and IPCS peak force; small reductions to CMJ jump height (JH) (flight time), eccentric peak force and eccentric deceleration rate of force development and moderate to large reductions to perceived fatigue, muscle soreness and mood. No match-induced changes were observed for CMJ flight time: contraction time or eccentric duration. Posterior chain, abductor, CMJ and self-report measures normalised by MD+3 but adductor peak force remained compromised at MD+3 (ES = small). Posterior chain, adductor and abductor peak isometric force and maximal impulse; CMJ JH, eccentric peak force and eccentric deceleration rate of force development and perceived fatigue, muscle soreness and mood are sensitive to match-induced fatigue. Since adductor peak force remained compromised at MD+3, it is apparent that players might not achieve complete neuromuscular recovery within 3 days of match play, and that the adductor muscle group might be particularly vulnerable to match-induced fatigue.

Validity, Agreement and Reliability of the ForceFrame Dynamometer in Patients with Anterior Cruciate Ligament Injury

Background

Restoring maximal muscle strength of the knee extensors (KE) and knee flexors (KF) following anterior cruciate ligament (ACL) injury and ACL reconstruction is of great importance to reduce the re-injury rate after ACL reconstruction and to reduce the risk of knee osteoarthritis. Therefore, it is essential that clinicians and healthcare providers use valid and reliable measures to assess knee muscle strength to ensure a safe return to sport.

Purpose

To evaluate the reliability (test-retest reliability, inter-tester reliability and test-retest agreement) and validity (concurrent validity, convergent validity and ForceFrame (FF) vs. isokinetic dynamometer (ID) agreement) of the ForceFrame (FF) dynamometer during isometric testing of the knee extensors and flexors.

Study Design

Cross-sectional study.

Material and Methods

Twenty-seven participants with ACL injury or reconstruction were recruited for participation in this study. maximal voluntary isometric contration (MVIC) of the knee extensors and flexors was tested on two separate days. Day one included validity assessments with FF, a gold-standard ID and a handheld dynamometer (HHD). Day two included reliability assessments with FF performed by two assessors. Main outcome measures were day-to-day test-retest reliability and agreement and inter-tester reliability of FF, and concurrent validity (FF vs. an ID and a HHD). Reliability was tested as test-retest and inter-tester reliability using interclass correlation coefficient (ICC), while agreement was tested using Bland & Altman plots with limits of agreement (LOA), standard error of measurement (SEM) and smallest detectable change (SDC). Concurrent validity between FF, ID, and HHD was assessed using Pearson's correlations and mean difference was evaluated by Bland & Altman plots.

Results

Twenty-seven participants (10 females, 17 males) with a median age of 25 years (range 19-60) were included in this study. There was a good day-to-day test-retest reliability for MVIC of KE (ICC=0.77, CI95:0.48-0.90) and KF (ICC=0.83, CI95:0.61-0.92) and excellent inter-tester reliability for MVIC of KE (ICC=0.97, CI95:0.94-0.98) and KF (ICC=0.93, 95CI:0.85-0.97). Standard error of measurement (SEM) was 8% and 9%, while the smallest detectable change (SDC) was 22% and 27% for KE and KF, respectively. FF showed fair concurrent validity compared to ID for KE (r=0.56), poor concurrent validity for knee flexors (KF (r=0.24) and compared to HHD a moderate correlation for KE (r=0.74) and poor correlation for KF (r=0.12). Bland & Altman plots between FF and the ID showed a mean difference of -0.51 Nm/kg for KE and -0.32Nm/kg for KF.

Conclusions

FF can be used to obtain reliable and valid results to assess MVIC of the KE, but not the KF. It should be noted that absolute results produced by the FF may be considered an underestimation of actual MVIC. The test position to assess KF in FF does not appear to be optimal, and different test-positions may be considered.

Level of evidence

Level 3.

Hip adduction and abduction strength values in elite-level male and female youth soccer players: A comparison between sexes, and across age-groups

OBJECTIVES

To report isometric hip adduction squeeze and abduction press strength values of elite-level youth male and female soccer players and examine if differences exist between sexes, and age-groups.

DESIGN

Cross-sectional cohort study.

SETTING

Elite youth soccer academy.

PARTICIPANTS

102 soccer players (n = 64; male, n = 38 female) competing in the national youth soccer leagues from under (U) 14-19 years of age level (U-14, U-15, U-17, U-19).

MAIN OUTCOME MEASURES

Isometric hip adduction and abduction strength values were measured with a ForceFrame in various testing positions.

RESULTS

Isometric hip adduction and abduction strength values are presented. Male U-17 and U-19 players demonstrated significantly greater (p < 0.05) absolute(N) and relative (N/kg) hip adduction and abduction strength than their female counterparts, with large (η2 = 0.068-0.227) and medium-to-large (η2 = 0.049-0.234) effect size, respectively. Significant differences in absolute strength, but not relative strength, were observed for hip adduction and abduction between male age-groups (U-14, U-15, U-17, U-19), with hip abduction strength differences only existing between U-14 and U-17 groups. No significant differences in hip strength were observed between U-17 and U-19 groups for female players.

CONCLUSION

Male youth soccer players have higher absolute and relative hip adduction and abduction strength than females at the U-17 and U-19 level.

Assessment of hip abductor and adductor muscle strength with fixed-frame dynamometry: Considerations on the use of bilateral and unilateral tasks

OBJECTIVE

To examine the specificities and limitations of bilateral and unilateral tasks for the assessment of hip abductor and adductor strength with a commercially-available fixed-frame dynamometer.

DESIGN

Correlational/validity study.

METHODS

Maximal voluntary isometric strength of hip abductors and adductors was evaluated in 130 healthy participants using unilateral and bilateral tasks. Surface EMG activity of agonist and stabilizer muscles was concomitantly recorded in a subgroup of 15 participants.

RESULTS

For both muscle groups, bilateral tasks resulted in higher strength values than unilateral tasks (∼25%; p < 0.001). The correlation between left- and right-side data was higher for bilateral than unilateral tasks (p < 0.05), thereby resulting in lower interlimb asymmetries (p < 0.001). Agonist EMG activity was lower for unilateral than bilateral tasks (p < 0.01). Stabilizer EMG activity (external abdominal oblique) was higher for unilateral than bilateral tasks (p < 0.05) on the ipsilateral and contralateral side for hip abductors and adductors, respectively.

CONCLUSIONS

A large (25%) and quasi-systematic bilateral facilitation of strength was observed for both hip abductors and adductors. Bilateral testing led to an underestimation of interlimb asymmetries, due to higher side equivalence than unilateral tasks. Unilateral testing resulted in lower agonist EMG activity and higher stabilizer activity than bilateral tasks, especially in weaker subjects.

The Strength and Power Profile of Junior and Senior Female Rugby League Athletes

ABSTRACT

Flannery, L, Secomb, JL, West, MA, Compton, HR, and Dascombe, BJ. The strength and power profile of junior and senior female rugby league athletes. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to compare the lower-body strength and power profiles of the various female rugby league (RL) competition levels, thereby establishing normative data for these athletes. Seventy-nine female RL athletes from 3 different competition levels: junior-state (n = 45, age: 17.5 ± 0.6 years), senior-state (n = 15, age: 24.3 ± 3.7 years), and senior-national (n = 19, age: 25.4 ± 4.0 years) participated in this study. All testing was completed in a single session at the beginning of preseason, with the following assessments performed: countermovement jump (CMJ), isometric mid-thigh pull (IMTP), and bilateral and unilateral isometric hip adduction and abduction strength. One-way analyses of variance with Bonferroni post hoc analyses, revealed that junior-state athletes exhibited significantly lower IMTP peak force (PF) and relative PF (rPF), and CMJ height compared with the senior-state and senior-national athletes. Importantly, senior-national athletes demonstrated significantly greater body mass (80.9 ± 14.6 kg) than senior-state athletes (70.9 ± 8.1 kg), but no significant differences were identified between these athletes for any IMTP or CMJ measure. Finally, the senior-national athletes possessed significantly lower unilateral hip adduction rPF (0.13 ± 0.04 N·BW-1) and adduction to abduction strength ratio (0.92 ± 0.14) than senior-state athletes (0.17 ± 0.03 N·BW-1 and 1.04 ± 0.13, respectively), which may have implications for noncontact lower-body injury risk. This study highlights the importance of practitioners prescribing training to increase the lower-body strength and power of junior-state RL athletes. Whereas, for senior-state athletes progressing to senior-national levels, the focus should on maintaining or improving relative strength and power, while increasing their body mass to enhance preparedness for the greater contact demands at that level.

Changes in Hip Isometric Strength of Female College Soccer Players After High-Workload Training Session

CONTEXT

The hip adductor and abductor muscles play vital roles as stabilizers in the lower-extremity. Their activation during soccer-specific actions is essential, but local muscular fatigue can hinder athletic performance and increase the risk of injury.

DESIGN

This study aimed to observe the variations in frontal plane hip strength in female college soccer players before and after a high-workload soccer-specific training session. Furthermore, the study sought to compare the relative changes in hip strength with the internal and external load measures obtained during that session.

METHODS

Twenty female college soccer players participated in a retrospective observational study. Isometric hip adductor and abductor strength were measured before and after a training session in the college spring season. Measurements were taken with a handheld dynamometer (MicroFET 2) while the players were supine. Global positioning system sensors (Catapult Vector S7), commonly worn by players during training sessions and competitive matches, were used to measure external and internal loads. Statistical analyses were performed using paired samples t test to assess hip adductor and abductor strength changes before and after the training session. Spearman rank was used to identify correlation coefficients between global positioning system data and isometric hip strength.

RESULTS

The findings revealed significant decreases in the strength of the right hip adduction (P = .012, -7% relative change), right abduction (P = .009, -7.6% relative change), and left abduction (P = .016, -4.9% relative change) after the training session. Furthermore, relative decreases in hip isometric adduction and abduction strength are related to the distance covered at high speeds.

CONCLUSION

The results of this study highlight that hip isometric adduction and abduction strength tend to decrease after exposure to high workloads during soccer-specific training.

Test-retest reliability and concurrent validity of knee extensor strength measured by a novel device incorporated into a weight stack machine vs. handheld and isokinetic dynamometry

BACKGROUND

The current clinical gold standard for assessing isometric quadriceps muscle strength is an isokinetic dynamometer (IKD). However, in clinics without an IKD, clinicians default to using handheld dynamometers (HHD), which are less reliable and accurate than the IKD, particularly for large muscle groups. A novel device (ND) was developed that locks the weight stack of weight machines, and measures forces applied to the machine, turning this equipment into an isometric dynamometer. The objectives of this study were to characterize the test-retest reliability of the ND, determine the within-day and between-days inter-rater reliability and concurrent validity compared with that of the HHD, in healthy volunteers (HV) and individuals with knee osteoarthritis (OA) for measuring knee extensors isometric muscle force.

MATERIALS AND METHODS

29 healthy (age = 28.4 ± 7.4 years) and 15 knee OA (age = 37.6 ± 13.4 years) participants completed three maximum force isometric strength testing trials on dominant side knee extensor muscles on three devices (ND, HHD, and IKD) in two separate sessions by two raters. The maximum force (Fmax) produced, and the force-time series were recorded. Reliability and validity were assessed using Intraclass Correlation Coefficient (ICC), Bland-Altman Plots, Pearson's r, and cross-correlations.

RESULTS

The ND demonstrated excellent test-retest reliability (ICC2,3 = 0.97). The within-day (ICC2,3 = 0.88) and between-day inter-rater reliability (ICC2,3 = 0.87) was good for HHD. The ND showed excellent within-day (ICC2,3 = 0.93) and good between-day (ICC2,3 = 0.89) inter-rater reliability. The Bland-Altman analysis revealed HHD systematic bias and underestimation of force particularly with quadriceps force values exceeding 450 N. Mean differences were found in maximum force between HHD vs. IKD (MDabs = 58 N, p < .001) but not the HHD vs. ND (MDabs = 24 N, p = .267) or ND vs. IKD (MDabs = 34 N, p = .051). The concurrent validity of Fmax (r = 0.81) and force-time curve correlation (0.96 ± 0.05) were the highest between the ND and IKD.

CONCLUSIONS

The ND's test-retest reliability and concurrent validity make it a potential strength assessment tool with utility in physical therapy and fitness settings for large muscle groups such as the knee extensors.

Identification of potential risk factors for lower limb injuries in female team-sport athletes: a prospective cohort study

OBJECTIVES

The purpose of this prospective cohort study was to assess the associations between lower limb injuries in female team-sport athletes and a number of factors. The potential risk factors explored included (1) lower limb strength, (2) history of life-event stress, (3) family history of ACL injuries, (4) menstrual history, and (5) history of oral contraception use.

METHODS

One hundred and thirty-five female athletes aged between 14 and 31 years (mean: 18.8 ± 3.6 years) from rugby union (n = 47), soccer (n = 72), and netball (n = 16) volunteered to participate in this study. Demographics, history of life-event stress, injury history and baseline data were obtained prior to the competitive season. The following strength measures were collected: isometric hip adductor and abductor strength, eccentric knee flexor strength and single leg jumping kinetics. Athletes were then followed for 12 months, and all lower limb injuries sustained were recorded.

RESULTS

One hundred and nine athletes provided one-year follow-up injury data, of whom, 44 suffered at least one lower limb injury. All athletes who reported high scores for negative life-event stress sustained lower limb injuries. Non-contact lower limb injury was positively associated with weak hip adductor strength (OR: 0.88; 95%CI: 0.78-0.98; p = 0.017), and between-limb adductor (OR: 5.65; 95%CI: 1.61-19.7.; p = 0.007) and abductor (OR: 1.95; 95%CI: 1.03-3.71; p = 0.039) strength asymmetries.

CONCLUSION

History of life event stress, hip adductor strength, and between-limb adductor and abductor strength asymmetries offer potential novel avenues for investigating injury risk factors in female athletes.

Reliability of Measures of Lower-Body Strength and Speed in Academy Male Adolescent Soccer Players

ABSTRACT

Ferguson, J, Gibson, NV, Weston, M, and McCunn, R. Reliability of measures of lower body strength and speed in academy male adolescent soccer players. J Strength Cond Res 38(3): e96-e103, 2024-The Nordbord and ForceFrame represent a practical and time efficient means of assessing eccentric hamstring and isometric adductor strength in the large number of squads and players associated with youth soccer academies, yet measurement reliability in this population is unexamined. Therefore, over a period of 4 days, with no less than 24 hours and no more than 48 hours between trials, 37 players (age: 14.7 ± 0.8 years, stature: 168.7 ± 7.8 cm, mass: 57.7 ± 9.1 kg, and maturity offset: 0.8 ± 0.9 years) were assessed for eccentric hamstring strength (force, torque), isometric adductor strength (long and short lever positions), and 30-m sprint (5, 10, and 20-m splits), using the Nordbord, ForceFrame, and electronic timing gates, respectively, on 3 separate occasions. Relative reliability (intraclass correlation coefficient) was rated as good for all Nordbord (range: 0.86-0.89) and ForceFrame (0.78-0.85) measures and ranged from moderate (0.53) to excellent (0.93) for the speed measures, improving with increased distance. Absolute reliability (standard error of the measurement [%SEM]) ranged from 7 to 8% (Nordbord), 3 to 11% (ForceFrame), and 1 to 4% (sprints). Our data provide the first Nordbord and ForceFrame reliability estimates in adolescent soccer academy players. To interpret test sensitivity, practitioners are encouraged to interpret our estimates of absolute reliability against meaningful change values derived from personal experience and evidence-based knowledge and not against absolute or standardized thresholds.

Inter- and intra-session variability of compression strain gauge for the adductor groin squeeze test on soccer athletes

The importance of hip adductor strength for injury prevention and performance benefits is well documented. The purpose of this study was to establish the intra- and inter-day variability of peak force (PF) of a groin squeeze protocol using a custom-designed compression strain gauge device. Sixteen semi-professional soccer players completed three trials over three separate testing occasions with at least 24-h rest between each session. The main findings were that the compression strain gauge was a reliable device for measuring PF within and between days. All intraclass correlations were higher than 0.80 and coefficients of variations were below 10% across the different sessions and trials. Due to the information gained through the compression strain gauge, the higher sampling frequency utilized, portability, and the relatively affordable price, this device offers an effective alternative for measuring maximal strength for hip adduction.

Hip Muscle Strength, Range of Motion, and Functional Performance in Young Elite Male Australian Football Players

CONTEXT

Hip and groin injuries are common in field sports such as football, with measurement of hip strength and range of motion (ROM) recommended for assessment of these conditions. We aimed to report hip strength, hip ROM, and functional task performance in young elite Australian football athletes.

DESIGN

Cross-sectional study.

METHODS

Fifty-eight newly drafted Australian Football League athletes completed hip abduction, adduction, internal rotation, external rotation, and flexion strength testing with an adjustable stabilized or hand-held dynamometer. Hip internal rotation and external rotation, bent knee fall out, and ankle dorsiflexion ROM were also measured. Players completed hop for distance, side bridge, and star excursion balance functional tests. We compared findings between the dominant and nondominant limbs.

RESULTS

We found small deficits unlikely to be clinically meaningful in the dominant limb for hip abduction and adduction strength, and a small deficit in the nondominant limb for external rotation strength and side bridge time. Athletes had lower hip internal rotation (mean difference 2.56°; 95% confidence interval, 0.87 to 4.26) and total rotation ROM (2.03°; 95% confidence interval, 0.06 to 4.01) on the dominant limb.

CONCLUSIONS

There were no meaningful differences between dominant and nondominant limbs for hip strength, ROM, or functional tests. Our results may be used for benchmarking young male Australian football athletes when targeting optimal strength and returning from injury.

Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers

Background

Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance.

Purpose

The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers.

Study Design

Cross-sectional study (retrospective).

Methods

Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO2max testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history.

Results

The breakers had a median 11.0 [10.0 - 14.0] years breaking experience and trained 24.4 [20.5 - 30.0] hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without.

Conclusion

The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking.

Level of Evidence

2b.

The Relationship of Anthropometric and Physical Performance Characteristics on Competitive Success in Amateur, Elite, and Professional Rodeo Athletes

ABSTRACT

Oranchuk, DJ, Gullett, LK, Kicia, M, Thome, B, and Game, A. The relationship of anthropometric and physical performance characteristics on competitive success in amateur, elite, and professional rodeo athletes. J Strength Cond Res 37(7): 1495-1506, 2023-Reference anthropometric and physical performance qualities can improve understanding of sporting needs and streamline preparation and rehabilitation programs. However, these data and their relationships with competitive success are absent in rodeo athletes. We hypothesized that riding performance would be most correlated with hip adductor, neck, and grip strength, whereas jump, reactive strength index (RSI), and change of direction abilities would best predict bull-fighting performance. Forty-three amateur ( n = 9), professional ( n = 23), or internationally ranked ( n = 11) male rodeo athletes (bareback = 9, bull riders = 16, saddle bronc = 7, bullfighters = 11) (26.8 ± 5.6 years) volunteered for this study. Anthropometrics included body mass, height, and body fat percentage. Performance measures included isometric hip adduction and abduction, neck flexion and extension, handgrip strength, squat and countermovement jump heights, eccentric utilization ratio, reactive strength index, change of direction, bike sprints, and several pneumatic power measures. Bullfighters were taller and heavier than bull riders (effect size [ES] = 0.84-0.87, p = 0.008-0.017). Bull riders were leaner than bullfighters (ES = 0.74, p = 0.012). Fighters had greater RSI than riders (ES = 0.73-1.47, p < 0.001-0.030). Competitive level of rodeo riders ( n = 32) correlated with age, rodeo experience (ρ = 0.37-0.43, p = 0.013-0.049), bent-leg abduction (ρ = 0.43, p = 0.014), straight-leg hip adduction and abduction (ρ = 0.49-0.56, p < 0.001-0.005), neck flexion force (ρ = 0.43, p = 0.016), and rotational power (ρ = 0.50, p = 0.004). The competitive level of the fighters correlated with age (ρ = 0.64, p = 0.036) and time trial performance (ρ = -0.76, p = 0.006). This is the first study providing normative and correlational strength and power performance data in a rodeo population. These data highlight the need for more event-specific physical preparation. Riders should focus their physical preparation on hip and neck strength and rotational power. Bullfighters should prioritize stiffness and anaerobic power.

Hip Strength Profiling of Ice Hockey Athletes Across Various Joint-Specific Angles: Monitoring and Injury Implications

ABSTRACT

Secomb, JL, Kelly, M, and Dascombe, BJ. Hip strength profiling of ice hockey athletes across various joint-specific angles: monitoring and injury implications. J Strength Cond Res 37(7): e422-e429, 2023-The purpose of this research was to compare the hip adduction and abduction relative strength, adduction-to-abduction strength ratio (ADD:ABD), and interlimb asymmetries of ice hockey athletes between the typically used bilateral position and 3 unilateral positions in joint-specific angles (0°, 25°, and 50° of hip abduction) relevant to an ice hockey stride. A secondary purpose was to explore any relationships between these measures and hip and groin noncontact injuries, and self-reported pain and disability. Twenty-five semiprofessional male ice hockey athletes (26.7 ± 6.7 years) were assessed for hip abduction range of motion (ROM), hip adduction and abduction relative strength, and completed the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire. Within-subjects repeated-measures analysis of variance revealed a significant effect for the assessment position for adduction ( F1,24 = 52.4, p < 0.01) and abduction relative strength ( F1,24 = 152.1, p < 0.01), ADD:ABD ( F1,24 = 38.9, p < 0.01), and the interlimb asymmetries for each of these variables ( F1,24 = 9.8-12.3; p < 0.01), with large strength differences observed between the bilateral assessment and all unilateral assessment positions for adduction and abduction relative strength. In addition, 4 athletes experienced a noncontact hip or groin injury within 1 month after testing, and when compared with the rest of the cohort ( n = 21) with Welch's t -tests, demonstrated significantly reduced hip abduction ROM (mean difference [MD] = -8.4 ± 2.5°; p < 0.01), sport subscale score for the HAGOS questionnaire (MD = -33.9 ± 7.1; p < 0.01), and a decline in hip adduction relative strength in the unilateral position of 50° compared with the position of 25° hip abduction (MD = -13.4 ± 3.8; p = 0.04). These results suggest that practitioners working with ice hockey athletes may benefit from profiling hip strength in these unilateral joint-specific angle positions because they provide an evidence base to determine the hip strength needs of ice hockey athletes in positions associated with skating performance and noncontact hip and groin injury mechanisms (between 25° and 50° of hip abduction).

Hip muscle strength in male and female patients with femoroacetabular impingement syndrome: Comparison to healthy controls and athletes

OBJECTIVES

To examine hip muscle strength deficits in patients with femoroacetabular impingent syndrome (FAIS), with special emphasis on potential sex- and comparison-related (between-subject vs within-subject) differences.

DESIGN

Cross-sectional comparative study.

PARTICIPANTS

Forty FAIS patients (20 women), 40 healthy controls (20 women) and 40 athletes (20 women).

MAIN OUTCOME MEASURES

Hip abduction, adduction and flexion isometric strength was tested using a commercially-available dynamometer. Two between-subject comparisons (FAIS patients vs controls and FAIS patients vs athletes) and one within-subject comparison (inter-limb asymmetry) of strength deficits were conducted, based on the calculation of respective percent differences.

RESULTS

For all hip muscle groups, women were 14-18% weaker than men (p < 0.001), but no sex-related interactions were observed. For all hip muscle groups, FAIS patients were 16-19% weaker than controls (p = 0.001) and 24-30% weaker than athletes (p < 0.001). For FAIS patients, the involved hip abductors were 8.5% weaker than the uninvolved ones (p = 0.015), while no inter-limb asymmetry was observed for the other hip muscles.

CONCLUSION

Sex had no influence on hip muscle strength deficits in FAIS patients while a major impact of comparison method/group was observed. Hip abductors showed consistent deficits for all comparison methods, suggestive of a possible greater impairment compared to hip flexors and adductors.

Gluteal Muscle Forces during Hip-Focused Injury Prevention and Rehabilitation Exercises

PURPOSE

This study aimed to compare and rank gluteal muscle forces in eight hip-focused exercises performed with and without external resistance and describe the underlying fiber lengths, velocities, and muscle activations.

METHODS

Motion capture, ground reaction forces, and electromyography (EMG) were used as input to an EMG-informed neuromusculoskeletal model to estimate gluteus maximus, medius, and minimus muscle forces. Participants were 14 female footballers (18-32 yr old) with at least 3 months of lower limb strength training experience. Each participant performed eight hip-focused exercises (single-leg squat, split squat, single-leg Romanian deadlift [RDL], single-leg hip thrust, banded side step, hip hike, side plank, and side-lying leg raise) with and without 12 repetition maximum (RM) resistance. For each muscle, exercises were ranked by peak muscle force, and k-means clustering separated exercises into four tiers.

RESULTS

The tier 1 exercises for gluteus maximus were loaded split squat (95% confidence interval [CI] = 495-688 N), loaded single-leg RDL (95% CI = 500-655 N), and loaded single-leg hip thrust (95% CI = 505-640 N). The tier 1 exercises for gluteus medius were body weight side plank (95% CI = 338-483 N), loaded single-leg squat (95% CI = 278-422 N), and loaded single-leg RDL (95% CI = 283-405 N). The tier 1 exercises for gluteus minimus were loaded single-leg RDL (95% CI = 267-389 N) and body weight side plank (95% CI = 272-382 N). Peak gluteal muscle forces increased by 28-150 N when exercises were performed with 12RM external resistance compared with body weight only. Peak muscle force coincided with maximum fiber length for most exercises.

CONCLUSIONS

Gluteal muscle forces were exercise specific, and peak muscle forces increased by varying amounts when adding a 12RM external resistance. These findings may inform exercise selection by facilitating the targeting of individual gluteal muscles and optimization of mechanical loads to match performance, injury prevention, or rehabilitation training goals.

Reliability and validity of common hip adduction strength measures: The ForceFrame strength testing system versus the sphygmomanometer

OBJECTIVES

The criterion validity of the sphygmomanometer was evaluated, relative to the Force Frame strength testing system. Test-retest reliability was assessed for both hip adduction and abduction strength.

DESIGN

Test-retest reliability study and criterion validity study.

PARTICIPANTS

50 asymptomatic, field-sport athletes.

MAIN OUTCOME MEASURES

Maximal isometric hip adduction and abduction strength were measured. Interclass correlation coefficient(ICC_2,1) with confidence intervals were calculated to evaluate reliability of peak strength values. A Pearson product-moment correlation coefficient(r) was calculated to examine criterion validity of the sphygmomanometer as a measure of force when compared to the ForceFrame.

RESULTS

Intra-rater reliability for bilateral adduction testing using both ForceFrame and sphygmomanometer values revealed good-excellent reliability for both the 0° (ICC_2.1 = 0.87-0.90) and 45° (ICC_2.1 = 0.81-0.91) positions. ForceFrame values revealed good-excellent reliability for 0° abduction position and 45° abduction position. A good-moderate relationship (Pearson's r = 0.63) for 0° adduction position, and poor relationship (Pearson's r = 0.40) for 45° adduction position, were found between adduction squeeze values on ForceFrame and sphygmomanometer.

CONCLUSION

Excellent reliability in hip adduction squeeze strength testing for both modes. However, there exists a 'good to moderate'-'fair' relationship between the Force Frame and sphygmomanometer.

Validity, reliability, minimal detectable change, and methodological considerations for HHD and portable fixed frame isometric hip and groin strength testing: A comparison of unilateral and bilateral testing methods

OBJECTIVES

Comparative assessment of bilateral (KangaTech) and unilateral (HHD) testing modalities through concurrent validity and test-retest reliability. Methodological considerations explored include minimum repetitions and comparison of average and maximum values.

DESIGN

Experimental, observational.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Thirty-three participants.

MAIN OUTCOME MEASURES

Concurrent validity using peak force. Test-retest reliability used Abduction and Adduction using 2 trials, randomised between devices. Maximum peak force and average of both trials were used.

RESULTS

HHD and KT360 are concurrently valid (r = 0.996); with no significant difference (z = -0.681). Excellent HHD reliability (ICC:0.92-0.96) and KT360 (ICC:0.89-0.97). Significant difference between max peak force and average peak force but within the calculated MDC(%). No significant differences between max peak force between trials. Spearman-Brown prophecy predicted excellent reliability for one trial (ICC:0.81-0.95). Bilateral facilitation was demonstrated using the KT360 with 94.6-101.2% increase in force compared to HHD.

CONCLUSIONS

With no significant difference between first and second max effort, and excellent prophesised reliability, one rep max effort should be acceptable to use. Body positioning within the KT360 seems to elicit bilateral facilitation rather than deficit, therefore unilateral and bilateral force values are not interchangeable.

Characteristics of Biomechanical and Physical Function According to Symptomatic and Asymptomatic Acetabular Impingement Syndrome in Young Adults

Femoroacetabular impingement (FAI) is caused by hip joint anomalies. Although asymptomatic and symptomatic FAI have been reported in young adults, information on biomechanical and functional characteristics of FAI is rare. We compared the subjective hip score, range of motion (ROM), dynamic balance, and hip strength between symptomatic FAI (FAIsym) and asymptomatic FAI (FAIasym) groups and healthy controls. Participants (n = 307; men: 155, women: 152) were classified according to morphological abnormalities and hip joint symptoms, comprising symptomatic FAI, asymptomatic FAI, and healthy controls. The Copenhagen Hip and Groin Outcome Score (HAGOS), hip ROM, Y-balance test (YBT), and isokinetic hip strength were measured. The types of FAI were not significantly differenent in both men and women. FAIsym exhibited significantly reduced HAGOS, whereas FAIasym showed no significant difference compared to the healthy group (men: healthy 91.7 vs. FAIasym 87.2 vs. FAIsym 49.9, women: healthy 91.7 vs. FAIasym 86.2 vs. FAIsym 53.9). Hip flexion, adduction, and internal and external rotation ROMs were only significantly reduced in symptomatic FAI. Asymptomatic and symptomatic FAI groups displayed significantly lower YBT scores than healthy controls (men healthy: 84.9 vs. FAIasym: 69.0 vs. FAIsym 58.7, women healthy 79.2 vs. FAIasym 64.0 vs. FAIsym 55.5). Isokinetic hip flexion, adduction, and abduction strengths were significantly lower in FAIsym. In conclusion, FAIasym showed no decrease in muscle strength but displayed reduced dynamic balance. Subjective satisfaction, ROM, muscle strength, and dynamic balance were lower in FAIsym compared to FAIasym and healthy groups.

Strength and Biomechanical Risk Factors for Noncontact ACL Injury in Elite Female Footballers: A Prospective Study

PURPOSE

This study aimed to determine if a preseason field-based test battery was prospectively associated with noncontact anterior cruciate ligament (ACL) injury in elite female footballers.

METHODS

In total, 322 elite senior and junior female Australian Rules Football and soccer players had their isometric hip adductor and abductor strength, eccentric knee flexor strength, countermovement jump (CMJ) kinetics, and single-leg hop kinematics assessed during the 2019 preseason. Demographic and injury history details were also collected. Footballers were subsequently followed for 18 months for ACL injury.

RESULTS

Fifteen noncontact ACL injuries occurred during the follow-up period. Prior ACL injury (odds ratio [OR], 9.68; 95% confidence interval (95% CI), 2.67-31.46), a lower isometric hip adductor to abductor strength ratio (OR, 1.98; 95% CI, 1.09-3.61), greater CMJ peak take-off force (OR, 1.74; 95% CI, 1.09-3.61), and greater single-leg triple vertical hop average dynamic knee valgus (OR, 1.97; 95% CI, 1.06-3.63) and ipsilateral trunk flexion (OR, 1.60; 95% CI, 1.01-2.55) were independently associated with an increased risk of subsequent ACL injury. A multivariable prediction model consisting of CMJ peak take-off force, dynamic knee valgus, and ACL injury history that was internally validated classified ACL injured from uninjured footballers with 78% total accuracy. Between-leg asymmetry in lower limb strength and CMJ kinetics were not associated with subsequent ACL injury risk.

CONCLUSIONS

Preseason field-based measures of lower limb muscle strength and biomechanics were associated with future noncontact ACL injury in elite female footballers. These risk factors can be used to guide ACL injury screening practices and inform the design of targeted injury prevention training in elite female footballers.

Monitorización y periodización del rendimiento desde la fisioterapia deportiva ¿Hacia dónde vamos?

RESUMEN Introducción El concepto de monitorización y periodización es un visión que se ha desarrollado en la última década, donde se busca que se pueda tener un control de la carga interna y externa en los deportistas de distintas disciplinas deportivas producidas por el proceso de interacción con variables de prescripción de ejercicio que causan modificaciones a nivel fisiológico, bioquímico, biomecanico, muscular, neuromuscular  ocasionando la tensión en los subsistemas del movimiento corporal humano generando adaptaciones especificas ante una carga determinada la cual puede ser medida mediante el uso de tecnología especifica o test indirectos Metodología Revisión de la literatura con la combinación de palabras clave como Monitoring, Performance, sports training load, Periodization en bases de datos como Pubmed, Ebsco, Medline, Scopus, Science Direct Resultados se pudo identificar 65 artículos que referencian la existencia  de herramientas tecnológicas para realizar un proceso de monitorización y periodización desde la rehabilitación , prevención, control de carga, recuperación y readaptación deportiva que permiten la generación de datos estadísticos y crear perfiles desde cada área de actuación del fisioterapeuta deportivo. Conclusión la fisioterapia es una profesión encargada de muchos procesos deportivos que deben ser monitorizados y generen datos que permitan estandarizar procesos, crear perfiles de seguimiento específicos para facilitar la toma de decisiones desde el equipo biomédico e investigaciones en el deporte de alto rendimiento fusionando la practica con la evidencia científica.

Strong, Fast, Fit, Lean, and Safe: A Positional Comparison of Physical and Physiological Qualities Within the 2020 Australian Women's Rugby League Team

ABSTRACT

Minahan, C, Newans, T, Quinn, K, Parsonage, J, Buxton, S, and Bellinger, P. Strong, Fast, Fit, Lean, and Safe: A positional comparison of physical and physiological qualities within the 2020 Australian Women's Rugby League team. J Strength Cond Res 35(12S): S11-S19, 2021-The purpose of the present study was to report the physical and physiological characteristics of elite women Rugby League (RL) players. Thirty-nine women (25.6 ± 4.3 years, 171.3 ± 7.7 cm, 83.5 ± 13.9 kg) from the 2020 Australian women's RL squad were recruited for this study. Players were categorized as adjustables (n = 7), backs (n = 15), or forwards (n = 17) for analysis. Each player was assessed for anthropometry, body composition (dual-energy X-ray absorptiometry), speed (5, 10 and 20 m sprint times), lower-body power (countermovement jump), upper-body power (medicine ball throw and explosive push up force), estimated one repetition maximum (e1RM) bench press, squat and bench pull, isometric mid-thigh pull strength, eccentric knee flexor strength, isometric hip abduction and adduction, and intermittent endurance performance (30-15 intermittent fitness test; 30-15 IFT). Linear mixed models were performed to compare positional groups. Forwards were significantly heavier and had greater fat mass, fat-free mass, and body fat percentage compared with backs and adjustables (P < 0.01). Backs were faster over 20 m compared with forwards (P = 0.025), whereas forwards had a lower 30-15 IFT peak velocity and estimated V̇o2peak compared with backs and adjustables. Nonetheless, when including body mass in the model, there were no differences between groups in 30-15 IFT peak velocity. There were no significant differences in other variables. These results provide contemporary benchmark physical, physiological, and anthropometric data for elite women RL players, which can inform recruitment, selection, training, and testing.

Impact of prior anterior cruciate ligament, hamstring or groin injury on lower limb strength and jump kinetics in elite female footballers

OBJECTIVE

To compare lower limb strength and countermovement jump (CMJ) kinetics between elite female footballers with and without a history of anterior cruciate ligament reconstruction (ACLR), hamstring strain, or hip/groin injury.

DESIGN

Cross-sectional.

SETTING

Field-based.

PARTICIPANTS

369 elite female Australian football, soccer and rugby league players aged 15-35.

MAIN OUTCOME MEASURES

Isometric hip adductor and abductor strength, eccentric knee flexor strength, and CMJ vertical ground reaction forces, including between-leg asymmetry. Players reported their lifetime history of ACLR, and whether they had sustained a hamstring strain, or hip/groin injury in the previous 12-months.

RESULTS

Players with a unilateral history of ACLR (n = 24) had significant between-leg asymmetry in eccentric knee flexor strength (mean = -6.3%, 95%CI = -8.7 to -3.9%, P < .001), isometric hip abductor strength (mean = -2.5%, 95%CI = -4.3 to -0.7%, P = .008), and CMJ peak landing force (mean = -5.5%, 95%CI = -10.9 to -0.1%, P = .046). Together, between-leg asymmetry in eccentric knee flexor strength, isometric hip abductor strength, and CMJ peak landing force distinguished between players with and without prior ACLR with 93% accuracy.

CONCLUSION

Elite female footballers with a history of ACLR, but not hamstring or hip/groin injury, exhibit persistent between-leg asymmetries in lower limb strength and jump kinetics following a return to sport.

Importance of Joint Angle-Specific Hip Strength for Skating Performance in Semiprofessional Ice Hockey Athletes

ABSTRACT

Secomb, JL, Dascombe, BJ, and Nimphius, S. Importance of joint angle-specific hip strength for skating performance in semiprofessional ice hockey athletes. J Strength Cond Res 35(9): 2599-2603, 2021-Ice hockey athletes with faster sprint acceleration and change-of-direction (COD) skating performance possess a competitive advantage. However, it is unknown whether joint angle-specific hip strength, in combination with measures known to relate to skating performance (e.g., countermovement jump [CMJ]), better explains skating performance. The purpose of this research was to determine whether hip strength in joint angles specific to skating positions and CMJ performance explains sprint skating acceleration and COD performance. Thirteen semiprofessional male hockey (26.7 ± 6.7 years; 88.4 ± 18.1 kg; 181.9 ± 5.4 cm) athletes were assessed for CMJ performance, hip abduction and adduction strength, 10-m sprint skating acceleration, and COD (505) performance. Linear multiple regressions to predict skating acceleration and COD performance were calculated with variables chosen based on functional justification and magnitude of correlation. Hip abductor relative peak force (rPF) at 25° of hip abduction and CMJ rPF explained 46.0% (adjusted) of variance in sprint acceleration performance (F[2,12] = 6.18, p = 0.02). Countermovement jump peak eccentric velocity, adductor rPF at 50° of hip abduction, and difference in abductor rPF between 50° and 25° of hip abduction explained 85.0% (adjusted) of the variance in 505 time (F[3,12] = 22.8, p < 0.001). Hip strength at joint angles functionally relevant to skating (e.g., at 25° and 50°), in combination with relevant CMJ variables, explained large and very large amounts of variance in sprint skating acceleration and COD performance in this cohort. The inclusion of joint angle-specific hip strength profiling to a physical performance testing battery may provide practitioners with more specific knowledge on the strength of the hip through abduction range of motion, which may affect skating performance.

Field based lower limb strength tests provide insight into sprint and change of direction ability in academy footballers

Conducting field-based strength assessments is embedded within football academy development processes. Yet, there is a limited understanding of how hip and groin strength assessments relate to vital game-based tasks such as sprinting and change of direction (COD) performance. Our aim was to explore field-based strength assessments and their relationships with both sprint and COD performance in male academy footballers. Participants (n = 146; age 14.2 ± 2.2 years; stature 166.3 ± 15.4 cm; body mass 55.6 ± 15.6 kg) performed maximal countermovement jump (CMJ), Nordic hamstring strength (NHS), isometric hip adductor (ADD)/abductor (ABD), 5 m, 10 m, 20 m sprints, and modified 505 agility test. All strength measures were allometrically scaled to account for body weight. Between-limb differences were reported as imbalance scores. Principal component analysis reduced sprint and COD variables to a single "running ability" component score. Scaled strength and imbalance, when controlled for age, were associated with "running ability" (adjusted R²  = 0.78, p < 0.001). Significant effects on "running ability" included the following: age, CMJ impulse, NHS, and hip-ADD. When the sprint and COD variables were explored independently, age and CMJ-impulse were featured in all sprint and COD models. For 10 m and 20 m sprint distances, hip-ADD emerged as a significant effect. Mean 505 performance was explained by age, CMJ-impulse, hip-ADD, but also with the addition of NHS. Our findings suggest that insight into the underpinning strength qualities of "running ability" of academy footballers can be obtained from a suite of field-based tests.

Reliability of hip muscle strength measured in principal and intermediate planes of movement

BACKGROUND

Muscle strength testing is widely used in clinical and athletic populations. Commercially available dynamometers are designed to assess strength in three principal planes (sagittal, transverse, frontal). However, the anatomy of the hip suggests muscles may only be recruited submaximally during tasks performed in these principal planes.

OBJECTIVE

To evaluate the inter-session reliability of maximal isometric hip strength in the principal planes and three intermediate planes.

METHODS

Twenty participants (26.1 ± 2.7 years, 50% female) attended two testing sessions 6.2 ± 1.8 days apart. Participants completed 3-5 maximal voluntary isometric contractions for hip abduction, adduction, flexion, extension, and internal and external rotation measured using a fixed uniaxial load cell (custom rig) and commercial dynamometer (Biodex). Three intermediate hip actions were also tested using the custom rig: extension with abduction, extension with external rotation, and extension with both abduction and external rotation.

RESULTS

Moderate-to-excellent intraclass correlation coefficients were observed for all principal and intermediate muscle actions using the custom rig (0.72-0.95) and the Biodex (0.85-0.95). The minimum detectable change was also similar between devices (custom rig = 11-31%; Biodex = 9-20%). Bland-Altman analysis revealed poor agreement between devices (range between upper and lower limits of agreement = 77-131%).

CONCLUSIONS

Although the custom rig and Biodex showed similar reliability, both devices may lack the sensitivity to detect small changes in hip strength commonly observed following intervention.

Reliability of a New Portable Dynamometer for Assessing Hip and Lower Limb Strength

The purpose of this study was to evaluate intra- and inter-session reliability of the new, portable, and externally fixated dynamometer called MuscleBoard® for assessing the strength of hip and lower limb muscles. Hip abduction, adduction, flexion, extension, internal and external rotation, knee extension, ankle plantarflexion, and Nordic hamstring exercise strength were measured in three sessions (three sets of three repetitions for each test) on 24 healthy and recreationally active participants. Average and maximal value of normalized peak torque (Nm/kg) from three repetitions in each set and agonist:antagonist ratios (%) were statistically analyzed; the coefficient of variation and intra-class correlation coefficient (ICC2,k) were calculated to assess absolute and relative reliability, respectively. Overall, the results display high to excellent intra- and inter-session reliability with low to acceptable within-individual variation for average and maximal peak torques in all bilateral strength tests, while the reliability of unilateral strength tests was moderate to good. Our findings indicate that using the MuscleBoard® dynamometer can be a reliable device for assessing and monitoring bilateral and certain unilateral hip and lower limb muscle strength, while some unilateral strength tests require some refinement and more extensive familiarization.

Strength development and non-contact lower limb injury in academy footballers across age groups

Non-contact lower limb injuries are common in academy football. Yet, the impact these injuries have on strength development in academy footballers remains unclear. This study aimed to investigate the impact of non-contact lower limb injury on hip, groin, and knee flexor strength development in male academy youth footballers. Furthermore, this study: reports normative strength data of emerging field-based tests that can be easily deployed in football academies; explores the effect of age on injury occurrence; and highlights the number of days lost from injury in male youth footballers. Assessments of hip adductor, abductor, and eccentric knee flexor strength were obtained from 195 academy football players during pre-season and at the end of season. In-season injuries were recorded by medical staff. Those footballers who sustained non-contact lower limb injury were compared with those who did not sustain a non-contact lower limb injury. No between-group differences were observed for any strength assessments when controlled for pre-season measures. Stronger footballers at pre-season experienced strength loses, while those weaker players gained strength across the season. Hip strength development was impaired in older age group footballers. Sustaining a non-contact lower limb injury had minimal impact on strength development. In the absence of in-season lower limb strength monitoring, development in academy youth footballers may not progress as expected, and in particular, stronger and older youth athletes may benefit from individualized strength training.

Short and long lever adductor squeeze strength values in 100 elite youth soccer players: Does age and previous groin pain matter?

OBJECTIVE

To examine adductor squeeze strength in elite youth soccer players by investigating the relationship of age and previous one-year groin pain on adductor squeeze force outputs, and to provide reference values for youth players.

DESIGN

Cross-sectional study.

PARTICIPANTS

Elite youth soccer players (n = 100; age 14.5 ± 1.9 years; height 168.0 ± 10.7 cm; mass 60.7 ± 13.0 kg) participated.

MAIN OUTCOME MEASURES

Adductor squeeze tests were captured in short and long lever positions, and groin pain assessed via subjective retrospective questionnaire. Multiple linear regressions were computed to compare the effects of age and previous one-year groin pain on adductor squeeze strength.

RESULTS

Raw adductor squeeze force values (N) had a moderate positive relationship with age (short r = 0.517, p < 0.001; long r = 0.457, p < 0.001), but not when force is normalized to body mass (N/kg; short r = 0.014, p = 0.444; long r = -0.173, p = 0.043). Previous groin pain did not have an effect on short or long lever squeeze strength. Reference values for long lever adductor squeeze strength (3.59 ± 0.77 Nm/kg) are provided.

CONCLUSION

Age and previous groin pain do not have an effect on adductor squeeze strength values in elite youth soccer players, so comparing values to the present adolescent cohort can be quickly interpreted without adjustment for age or previous injury.

Adductor Muscles Strength and Strength Asymmetry as Risk Factors for Groin Injuries among Professional Soccer Players: A Prospective Study

The aim of this study was to prospectively examine the association between isometric hip adductor strength and between-limb strength asymmetry to groin injuries in male professional soccer players. Isometric hip adductor strength and between-limb strength asymmetry of 45 professional outfield soccer players from three First Division teams were tested during the 2017/2018 preseason. Players were then monitored throughout the 2017/2018 season for groin injuries. Ten groin injuries were recorded. When compared with uninjured players, players who sustained groin injury had significantly lower strength of respective muscle groups and significantly higher between-limb strength asymmetries (all p < 0.05; ES = 1.16 and 0.88; mean % difference = 26% and 51%). Isometric hip adductor strength had a significant inverse relationship with the incidence of occurring groin injuries (p = 0.016). No significant relationship between hip adductor strength asymmetry and the incidence of future groin injury was observed (p = 0.09). Finally, players' age and previous groin injury were not significantly associated with the incidence of future groin injuries (all p > 0.05). These results generally suggest that isometric adductor strength is a significant predictor of future groin injuries in men's professional football; however, due to the relatively low sample size, further studies are required.

Preseason Hip/Groin Strength and HAGOS Scores Are Associated With Subsequent Injury in Professional Male Soccer Players

DESIGN

Prospective cohort.

OBJECTIVE

To explore the association between preseason assessments of (1) isometric hip adductor and abductor strength using a novel field test and (2) the Copenhagen Hip and Groin Outcome Score (HAGOS) and subsequent hip/groin injury in male professional soccer players.

METHODS

In total, 204 male elite soccer players from 10 professional A-League and English Football League Championship clubs underwent assessments of hip adductor and abductor strength and completed the HAGOS in the 2017-2018 preseason. All subsequent hip/groin injuries were reported by team medical staff. Data reduction was conducted using principal-component analysis. The principal component for the HAGOS and 3 principal components for strength and imbalance measures were entered, with age and prior hip/groin injury, into a multivariable logistic regression model to determine their association with prospectively occurring hip/groin injury.

RESULTS

Twenty-four players suffered at least 1 hip/groin injury throughout the 2017-2018 season. The principal component for between-limb abduction imbalance (peak strength in the preferred kicking limb - nonpreferred limb) (odds ratio [OR] = 0.58; 95% confidence interval [CI]: 0.38, 0.90; P = .011), the principal component for peak adduction and abduction strength (OR = 0.71; 95% CI: 0.51, 1.00; P = .045), and the principal component for the HAGOS (OR = 0.77; 95% CI: 0.62, 0.96; P = .022) were independently associated with a reduced risk of future hip/groin injury. Receiver operating characteristic curve analysis of the whole model revealed an area under the curve of 0.76, which indicates a fair combined sensitivity and specificity of the included variables but an inability to correctly identify all subsequently injured players.

CONCLUSION

Hip abduction imbalance favoring the preferred kicking limb, higher levels of hip adductor and abductor strength, and superior HAGOS values were associated with a reduced likelihood of future hip/groin injury in male professional soccer players. J Orthop Sports Phys Ther 2020;50(5):234-242. Epub 17 Sep 2019. doi:10.2519/jospt.2020.9022.

Field-based evaluation of hip adductor and abductor strength in professional male ice hockey players: Reference values and influencing factors

OBJECTIVES

To provide reference values and examine the influence of hip/groin pain on hip adductor and abductor strength in professional male ice hockey players, by using a straightforward 5-min procedure.

DESIGN

Cross-sectional study.

SETTING

On-field assessment of hip/groin muscle strength with dynamometry, together with the concomitant level of hip/groin pain with a visual analogue scale.

PARTICIPANTS

Professional male ice hockey players competing in the Swiss National League (n = 187).

MAIN OUTCOME MEASURES

Hip abductor strength, hip adductor strength and hip adductor:abductor ratio.

RESULTS

Reference values by playing position (goalkeepers, defenders and forwards) are provided for asymptomatic athletes. Players with hip/groin pain during adduction displayed lower hip adductor strength (p = 0.001) and hip adductor:abductor ratio (p = 0.012) than their symptom-free peers.

CONCLUSIONS

The presence of hip/groin pain during adductor testing may contribute to selective hip adductor weakness, whose cause-effect relation with possible groin problems remains to be demonstrated.