Do people with musculoskeletal pain differ from healthy cohorts in terms of global measures of strength? A systematic review and meta-analysis.

OBJECTIVE: It is currently unknown if people with musculoskeletal pain display different multi-joint strength capacities than healthy cohorts. The aim was to investigate whether people with musculoskeletal pain show differences in global measures of strength in comparison to healthy cohorts. DATA SOURCES: A systematic review was conducted using three databases (Medline, CINAHL and SPORTDiscus) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. REVIEW METHODS: Studies involving participants with painful musculoskeletal conditions and multi-joint strength assessment measured at baseline were included. A meta-analysis was also performed to compute standardized mean differences (± 95% confidence intervals), using Hedge's g, and examined the differences in multi-joint strength at baseline between participants with painful musculoskeletal conditions and healthy participants. RESULTS: In total, 5043 articles were identified, of which 20 articles met the inclusion criteria and were included in the qualitative analysis. The available evidence revealed that multi-joint strength values were limited to knee osteoarthritis, fibromyalgia, chronic low back pain, and rheumatoid arthritis. Only four studies were included in the quantitative synthesis and revealed that only small differences in both chest press (g = -0.34, 95% CI [-0.64, -0.03]) and leg press (g = -0.25, 95% CI [-0.49, -0.02]) existed between adult women with fibromyalgia and active community women. CONCLUSION: There is a paucity of multi-joint strength values in participants with musculoskeletal pain. Quantitative comparison with healthy cohorts was limited, except for those with fibromyalgia. Adult women with fibromyalgia displayed reduced multi-joint strength values in comparison to active community women.

The Effects of a 6-Week Unilateral Strength and Ballistic Jump Training Program on the Force-Velocity Profiles of Sprinting.

ABSTRACT: Bettariga, F, Maestroni, L, Martorelli, L, Turner, A, and Bishop, C. The effects of a 6-week unilateral strength and ballistic jump training program on the force-velocity profiles of sprinting. J Strength Cond Res 37(7): 1390-1396, 2023-The aims of this study were (a) to investigate the effects of a unilateral training program, compared with a control group, on a force-velocity (F-V) profile in soccer players and (b) to explore such effects on linear speed. Twenty-four soccer players, randomly assigned to a 6-week unilateral strength and ballistic jump training (UNI) ( n = 12) or a control group (CON) ( n = 12), performed 30-meter linear sprint test. Findings showed small-to-moderate improvements ( p < 0.05) in linear speed time ( g = 0.66-0.81) and in most F-V variables: maximal running velocity ( V0 ) ( g = 0 .81), maximal power output ( Pmax ) ( g = 0.49), maximal ratio of force ( RFmax ) ( g = 0.55), optimal velocity ( Vopt ) ( g = 0.83), and maximal speed ( g = 0.84) from pre- to post-intervention in the UNI group, whereas no meaningful changes were found in the CON group. The between-group comparison indicated small to large significant changes in V0 ( g = 0.95), RFmax ( g = 0.48), Vopt ( g = 0.95), maximal speed ( g = 0.98), and linear speed time performance ( g = 0.42-1.02), with the exception of the 0-5 meter distance, in favor of the UNI group. Thus, a unilateral strength and ballistic jump training program can be used to improve the F-V profile and linear speed performance of amateur soccer players.

Abnormal quantitative sensory testing is associated with persistent pain one year after TKA.

BACKGROUND: Up to 15% of patients report at least moderate persistent pain after TKA. Such pain may be associated with the presence of widespread hyperalgesia and neuropathic-type pain. QUESTIONS/PURPOSES: We asked if there was a difference among patients who report moderate to severe pain or no pain at least 12 months after TKA regarding (1) pressure pain threshold, (2) thermal (cold/heat) pain and detection thresholds, and (3) self-reported neuropathic pain. PATIENTS AND METHOD: Fifty-three volunteers were recruited from patients reporting no pain or moderate to severe pain, according to the Knee Society Score©. Differences between the moderate-to-severe and no-pain groups regarding pressure pain, heat and cold thresholds, and self-reported neuropathic-type pain were analyzed using independent t-tests. RESULTS: Patients in the moderate-to-severe pain group exhibited reduced pressure pain threshold in the knee with the TKA (p=0.025) and at the elbow (p=0.002). This group also showed greater pain sensitivity to cold at the knee (p=0.008) and elbow (p=0.010), and increased heat pain sensitivity at the elbow (p=0.032). Cold and heat detection thresholds were impaired in this group at the elbow (cold, p=0.034; heat, p=0.010), although only heat detection was impaired at the knee (p=0.009). The moderate-to-severe pain group also reported more neuropathic-type pain (p=0.001). CONCLUSION: Persistent pain after TKA was associated with widespread pressure, cold hyperalgesia, and greater neuropathic-type pain. LEVEL OF EVIDENCE: Level III, prognostic study.

Total Score of Athleticism: Profiling Strength and Power Characteristics in Professional Soccer Players After Anterior Cruciate Ligament Reconstruction to Assess Readiness to Return to Sport.

BACKGROUND: There is no consensus on the optimal testing procedure to determine return-to-sport (RTS) readiness after anterior cruciate ligament (ACL) reconstruction. Current approaches use limb symmetry across a range of tests, but this does not consider a patient's level of athleticism or benchmarks relative to his or her noninjured counterparts. PURPOSE: To examine the utility of the Total Score of Athleticism (TSA), a composite scale including strength, power, and reactive strength assessments, to aid RTS decision-making. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 95 professional soccer players (60 who underwent ACL reconstruction [mean age, 25.1 ± 12.6 years] and 35 who were uninjured [mean age, 23.8 ± 2.8 years]) completed a battery of tests including isokinetic knee extension and flexion torque, bilateral and unilateral countermovement jump height, relative peak power, and reactive strength index-modified. The TSA score (derived from Z scores) was calculated, and we (1) examined differences between the ACL-reconstructed and uninjured groups at the time of RTS, (2) assessed the predictive ability of the TSA to identify the player's status (ACL reconstruction vs uninjured control), and (3) included a case series to discuss the characteristics of players who sustained a subsequent injury within 4 months after RTS. RESULTS: A large difference between the ACL-reconstructed and uninjured groups in the TSA score (d = 0.84; P < .0001) was evident. For every additional increase of 1 unit in the TSA score, the odds of belonging to the ACL-reconstructed group decreased by 74% (95% CI, 0.19-0.56). By visual inspection, the frequency of reinjured players was higher in the low (4/7) TSA tertile compared with the medium (2/7) and high (1/7) TSA tertiles. CONCLUSION: Preliminary evidence indicates that the TSA may be a useful RTS readiness tool, as the composite score derived from strength and power measures was different in soccer players at the time of RTS after ACL reconstruction compared with healthy matched controls. There was also a higher frequency of low TSA scores in players who sustained a second injury after RTS. Therefore, it is recommended to routinely administer RTS tests encompassing strength, power, and reactive strength qualities each season across the largest possible number of players (ideally teammates).

Single leg drop jump is affected by physical capacities in male soccer players following ACL reconstruction.

Single leg drop jump (SLDJ) assessment is commonly used during the later stages of rehabilitation to identify residual deficits in reactive strength but the effects of physical capacity on kinetic and kinematic variables in male soccer players following ACL reconstruction remain unknown. Isokinetic knee extension strength, kinematics from an inertial measurement unit 3D system and SLDJ performance variables and mechanics derived from a force plate were measured in 64 professional soccer players (24.7 ± 3.4 years) prior to return to sport (RTS). SLDJ between-limb differences was measured (part 1) and players were divided into tertiles based on isokinetic knee extension strength (weak, moderate and strong) and reactive strength index (RSI) (low, medium and high) (part 2). Moderate to large significant differences between the ACL reconstructed and uninjured limb in SLDJ performance (d = 0.92-1.05), kinetic (d = 0.62-0.71) and kinematic variables (d = 0.56) were evident. Stronger athletes jumped higher (p = 0.002; d = 0.85), produced greater concentric (p = 0.001; d = 0.85) and eccentric power (p = 0.002; d = 0.84). Similar findings were present for RSI, but the effects were larger (d = 1.52-3.84). Weaker players, and in particular those who had lower RSI, displayed landing mechanics indicative of a 'stiff' knee movement strategy. SLDJ performance, kinetic and kinematic differences were identified between-limbs in soccer players at the end of their rehabilitation following ACL reconstruction. Players with lower knee extension strength and RSI displayed reduced performance and kinetic strategies associated with increased injury risk.

Time to consider the potential role of alternative resistance training methods in cancer management?

Exercise has emerged as fundamental therapeutic medicine in the management of cancer. Exercise improves health-related outcomes, including quality of life, neuromuscular strength, physical function, and body composition, and it is associated with a lower risk of disease recurrence and increased survival. Moreover, exercise during or post cancer treatments is safe, can ameliorate treatment-related side effects, and may enhance the effectiveness of chemotherapy and radiation therapy. To date, traditional resistance training (RT) is the most used RT modality in exercise oncology. However, alternative training modes, such as eccentric, cluster set, and blood flow restriction are gaining increased attention. These training modalities have been extensively investigated in both athletic and clinical populations (e.g., age-related frailty, cardiovascular disease, type 2 diabetes), showing considerable benefits in terms of neuromuscular strength, hypertrophy, body composition, and physical function. However, these training modes have only been partially or not at all investigated in cancer populations. Thus, this study outlines the benefits of these alternative RT methods in patients with cancer. Where evidence in cancer populations is sparse, we provide a robust rationale for the possible implementation of certain RT methods that have shown positive results in other clinical populations. Finally, we provide clinical insights for research that may guide future RT investigations in patients with cancer and suggest clear practical applications for targeted cancer populations and related benefits.

Comparison of Strength and Power Characteristics Before ACL Rupture and at the End of Rehabilitation Before Return to Sport in Professional Soccer Players.

BACKGROUND: Strength and power is often reduced on the involved versus contralateral limb and healthy controls after anterior cruciate ligament (ACL) reconstruction, but no study has compared with preinjury values at the time of return to sport (RTS). HYPOTHESIS: Divergent recovery patterns in strength and power characteristics will be present at RTS relative to preinjury baseline data and healthy matched controls. STUDY DESIGN: Cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: Isokinetic strength tests, bilateral and single-leg countermovement jumps (CMJ; SLCMJ) were measured before ACL rupture in 20 professional soccer players. These then had surgical reconstruction (ACL group) and completed follow-up testing before RTS. Healthy controls (uninjured group) were tested at the same time as the ACL group preinjury. Values recorded at RTS of the ACL group were compared with preinjury. We also compared the uninjured and ACL groups at baseline and RTS. RESULTS: Compared with preinjury, ACL normalized quadriceps peak torque of the involved limb (difference = -7%), SLCMJ height (difference = -12.08%), and Reactive Strength Index modified (RSImod) (difference = -5.04%) were reduced after ACL reconstruction. No significant reductions in CMJ height, RSImod, and relative peak power were indicated at RTS in the ACL group when compared with preinjury values, but deficits were present relative to controls. The uninvolved limb improved quadriceps (difference = 9.34%) and hamstring strength (difference = 7.36%) from preinjury to RTS. No significant differences from baseline were shown in SLCMJ height, power, and reactive strength of the uninvolved limb after ACL reconstruction. CONCLUSION: Strength and power in professional soccer players at RTS after ACL reconstruction were often reduced compared with preinjury values and matched healthy controls. CLINICAL RELEVANCE: Deficits were more apparent in the SLCMJ, suggesting that dynamic and multijoint unilateral force production is an important component of rehabilitation. Use of the uninvolved limb and normative data to determine recovery may not always be appropriate.

What is the effect of ankle disk training and taping on proprioception deficit after lateral ankle sprains among active populations? - A systematic review.

OBJECTIVE: To investigate the effect of disk training and tape application on diminished proprioception after Lateral Ankle Sprain (LAS) in active populations. ELIGIBILITY CRITERIA: Only clinical trials investigating the effectiveness of disk training and ankle tape on proprioception deficits following LAS by assessing JPS or kinaesthesia were included. INFORMATION SOURCES: Electronic databases of PubMed, MEDLINE, SPORTDiscus, CINAHL, Web of Science, Cochrane and PEDro were searched. The main search was conducted in February 2022. RISK OF BIAS: The physiotherapy Evidence Database (PEDro) scale was utilised to assess the methodological quality of each article. RESULT: The search yielded six studies investigating the effects of disk training and four studies investigating the effects of inelastic tape. Five articles showed a significant improvement on JPS after disk training. However, no difference across different intervention groups was observed in one study. Only one trial presented an immediate significant improvement when taped, while another study showed that external ankle supports significantly improved JPS after 2 weeks and after 2 months. Three of four studies found no immediate improvement on proprioceptive deficits by the use of tape. CONCLUSIONS: This review found that disk training may improve impaired proprioception after LAS, whilst the efficacy of inelastic tape was not evident due to methodological quality of the few available studies. Further studies are needed to establish whether these interventions can be used clinically with sufficient evidence.

Relationships between physical capacities and biomechanical variables during movement tasks in athletic populations following anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction has a detrimental impact on athletic performance. Despite rehabilitation guidelines and criterion-based progressions to ensure safe restoration of fundamental physical capacities and maladaptive movement strategies, residual deficits in maximal strength, rate of force development (RFD), power and reactive strength are commonly reported. These combined with associated compensatory inter and intra-limb strategies increase the risk of re-injury. OBJECTIVE: The aim of this article is to examine the relationships between fundamental physical capacities and biomechanical variables during dynamic movement tasks. DESIGN: Narrative review. RESULTS: The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts in the later stages of rehabilitation and RTS CONCLUSION: The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts in the later stages of rehabilitation and RTS.

Strength, rate of force development, power and reactive strength in adult male athletic populations post anterior cruciate ligament reconstruction - A systematic review and meta-analysis.

BACKGROUND: Residual deficits in athletic performance are common despite rehabilitation guidelines following anterior cruciate ligament reconstruction including criterion-based progressions to protect healing structures, ensure safe restoration of fundamental physical capacities, and guide appropriate return to sports activities. A synthesis of the available literature is warranted to examine the physical readiness to re-perform of athletic populations in the later stages of rehabilitation in comparison to healthy controls. OBJECTIVES: To determine the level of strength, power, rate of force development, and reactive strength in adult males who are more than six months following anterior cruciate ligament reconstruction. METHODS: A systematic review of the literature was undertaken using the Medline, CINAHL and SPORTDiscus databases and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies including males only and assessed strength, power, rate of force development and reactive strength comparing performance to healthy controls were included. A meta-analysis was also performed to compute standardized mean differences (SMD ± 95% confidence intervals), calculated using Hedge's g, and examine the effect of ACLR on these fundamental physical capacities. RESULTS: 2023 articles were identified, of which 14 articles with similar level of evidence and methodological quality met the inclusion criteria. The most commonly investigated and impaired physical capacity was quadriceps (g = -0.89, 95% CI [-1.33,-0.44]) and hamstring strength (g = -0.44, 95% CI [-0.78,-0.10]). Only one study investigated rate of force development and none measuring reactive strength met our eligibility criteria. CONCLUSIONS: Pooled data showed moderate evidence indicating large and small negative deficits on knee peak extension and flexion, respectively, in male adults at more than 6 months post anterior cruciate ligament reconstruction. The magnitude of these differences are influenced by graft type and can be mitigated by targeted rehabilitation programs. Insufficient evidence is available in male adults following anterior cruciate ligament reconstruction to examine rate of force development and reactive strength.

Strength and Power Training in Rehabilitation: Underpinning Principles and Practical Strategies to Return Athletes to High Performance.

Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed.

Is rotator cuff related shoulder pain a multidimensional disorder? An exploratory study.

Background and aims Rotator cuff related shoulder pain has been associated with factors from multiple dimensions such as strength changes, psychosocial measures, comorbidities and level of education. However, to date little research has been undertaken to evaluate which factors explain the greatest variance in pain and disability levels in people with rotator cuff related shoulder pain. The objective of this study was therefore to evaluate which multidimensional examination findings were associated with higher pain and disability in a primary care cohort with rotator cuff related shoulder pain. Methods This was an exploratory cross-sectional cohort study. Sixty-seven participants with rotator cuff related shoulder pain were assessed for: pain intensity, disability; demographic, psychological, social and lifestyle characteristics, and isometric strength of shoulder internal and external rotator muscles. Univariable associations between pain intensity/disability and each variable were assessed using linear regression. Variables with univariable associations (p < 0.1) were entered into backwards stepwise multivariable regression models. Results The multivariable model for pain intensity included sleep and perceived persistence and explained 46.5% of the variance (37.6% uniquely by sleep, 5.4% uniquely by perceived persistence). The multivariable model for disability included sleep and sex and explained 26.8% of the variance (4.5% shared by predictors, 16.4% uniquely by sleep, 5.9% uniquely by sex). Conclusions Rotator cuff-related shoulder pain and disability are associated with sleep disturbance, perceived symptom persistence and sex. Rotator cuff related shoulder pain may be considered a multidimensional disorder. Implications Clinicians need to evaluate sleep and perceived symptom persistence in people with rotator cuff related shoulder pain. Future research may examine whether management strategies for RCRSP directed towards these factors afford improved treatment outcomes.

External rotator strength deficits in non-athletic people with rotator cuff related shoulder pain are not associated with pain intensity or disability levels.

BACKGROUND: Strength deficits are often reported in people with rotator cuff related shoulder pain. However, these have mainly been tested in athletic populations and pain interference with testing has not been considered. OBJECTIVES: To examine strength without pain interference in non-athletic people with rotator cuff related shoulder pain and its association with pain intensity and disability. DESIGN: Cross-sectional study. METHODS: Sixty-seven participants with rotator cuff related shoulder pain were assessed for isometric strength of shoulder external rotator and internal rotator muscles without pain interference with a hand-held dynamometer. Strength was normalized (%body weight). Differences in external and internal rotation strength and external:internal rotator strength ratio between symptomatic and asymptomatic sides were examined (Independent t-tests, Wilcoxon rank sum tests). Spearman's rank correlation coefficients were used to examine associations between strength and pain and disability levels. RESULTS: There was no significant difference in internal rotator strength normalized to body weight between symptomatic and asymptomatic sides. There was a significant difference in external rotator strength normalized to body weight (p < .001) and external:internal ratio (p < .001) between sides. No significant correlations were found between strength and pain or disability levels. CONCLUSION: Non-athletic people with rotator cuff related shoulder pain had external rotator strength deficits without pain interference during strength testing, which were not associated with pain and disability levels.

"Does isometric exercise improve leg stiffness and hop pain in subjects with Achilles tendinopathy? A feasibility study".

BACKGROUND: In Achilles tendinopathy (AT) the ability to store and recycle elastic energy during ground contact phase is often altered. A measure of this function is represented by leg stiffness (LS). Immediate responses in LS following therapeutic intervention have not been examined. OBJECTIVE: The aim of this paper was to examine the feasibility of the protocol in participants with AT. DESIGN: Single cohort feasibility study. PARTICIPANTS: Adults with persistent AT pain, symptoms on palpation and less than 80 points on the Visa-A questionnaire. INTERVENTION: heavy isometric exercise sequence in plantarflexion. OUTCOME MEASURES: Feasibility was assessed by evaluating: the willingness of participants to enroll into the study, the number of eligible participants, the recruitment rate, adherence to the intervention, the drop-out rate, the tolerability of the protocol. LS, reactive strength index, pain and rate of perceived effort were secondary outcomes. RESULTS: 22 AT were eligible for data collection and 19 entered the statistical analysis. The intervention was well tolerated, no withdrawals. Pain scores were low during both the intervention and the assessment. Immediate improvements in LS and pain were recorded. CONCLUSIONS: The isometric exercise protocol was feasible. Future research should investigate its effectiveness.

The Benefits of Strength Training on Musculoskeletal System Health: Practical Applications for Interdisciplinary Care.

Global health organizations have provided recommendations regarding exercise for the general population. Strength training has been included in several position statements due to its multi-systemic benefits. In this narrative review, we examine the available literature, first explaining how specific mechanical loading is converted into positive cellular responses. Secondly, benefits related to specific musculoskeletal tissues are discussed, with practical applications and training programmes clearly outlined for both common musculoskeletal disorders and primary prevention strategies.