The characteristics of the implicit body model of the trunk.

Knowing where the body is in space requires reference to a stored model of the size and shape of body parts, termed the body model. This study sought to investigate the characteristics of the implicit body model of the trunk by assessing the position sense of midline and lateral body landmarks. Sixty-nine healthy participants localised midline and lateral body landmarks on their thorax, waist and hips, with perceived positions of these landmarks compared to actual positions. This study demonstrates evidence of a significant distortion of the implicit body model of the trunk, presenting as a squatter trunk, wider at the waist and hips. A significant difference was found between perceived and actual location in the horizontal (x) and vertical (y) directions for the majority of trunk landmarks. Evidence of a rightward bias was noted in the perception of six of the nine body landmarks in the horizontal (x) direction, including all midline levels. In the vertical (y) direction, a substantial inferior bias was evident at the thorax and waist. The implicit body model of the trunk is shown to be distorted, with the lumbar spine (waist-to-hip region) held to be shorter and wider than reality.

Tactile localization accuracy at the low back.

Localizing tactile stimulation is an important capability for everyday function and may be impaired in people with persistent pain. This study sought to provide a detailed description of lumbar spine tactile localization accuracy in healthy individuals. Sixty-nine healthy participants estimated where they were touched at nine different points, labelled in a 3 × 3 grid over the lumbar spine. Mislocalization between the perceived and actual stimulus was calculated in horizontal (x) and vertical (y) directions, and a derived hypotenuse (c) mislocalization was calculated to represent the direct distance between perceived and actual points. In the horizontal direction, midline sites had the smallest mislocalization. Participants exhibited greater mislocalization for left- and right-sided sites, perceiving sites more laterally than they actually were. For all vertical values, stimulated sites were perceived lower than reality. A greater inaccuracy was observed in the vertical direction. This study measured tactile localization for the low back utilizing a novel testing method. The large inaccuracies point to a possible distortion in the underlying perceptual maps informing the superficial schema; however, further testing comparing this novel method with an established tactile localization task, such as the point-to-point method, is suggested to confirm these findings.

The clinical course of acute, subacute and persistent low back pain: a systematic review and meta-analysis.

BACKGROUND: Understanding the clinical course of low back pain is essential to informing treatment recommendations and patient stratification. Our aim was to update our previous systematic review and meta-analysis to gain a better understanding of the clinical course of acute, subacute and persistent low back pain. METHODS: To update our 2012 systematic review and meta-analysis, we searched the Embase, MEDLINE and CINAHL databases from 2011 until January 2023, using our previous search strategy. We included prospective inception cohort studies if they reported on participants with acute (< 6 wk), subacute (6 to less than 12 wk) or persistent (12 to less than 52 wk) nonspecific low back pain at study entry. Primary outcome measures included pain and disability (0-100 scale). We assessed risk of bias of included studies using a modified tool and assessed the level of confidence in pooled estimates using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. We used a mixed model design to calculate pooled estimates (mean, 95% confidence interval [CI]) of pain and disability at 0, 6, 12, 26 and 52 weeks. We treated time in 2 ways: time since study entry (inception time uncorrected) and time since pain onset (inception time corrected). We transformed the latter by adding the mean inception time to the time of study entry. RESULTS: We included 95 studies, with 60 separate cohorts in the systematic review (n = 17 974) and 47 cohorts (n = 9224) in the meta-analysis. Risk of bias of included studies was variable, with poor study attrition and follow-up, and most studies did not select participants as consecutive cases. For the acute pain cohort, the estimated mean pain score with inception time uncorrected was 56 (95% CI 49-62) at baseline, 26 (95% CI 21-31) at 6 weeks, 22 (95% CI 18-26) at 26 weeks and 21 (95% CI 17-25) at 52 weeks (moderate-certainty evidence). For the subacute pain cohort, the mean pain score was 63 (95% CI 55-71) at baseline, 29 (95% CI 22-37) at 6 weeks, 29 (95% CI 22-36) at 26 weeks and 31 (95% 23-39) at 52 weeks (moderate-certainty evidence). For the persistent pain cohort, the mean pain score was 56 (95% CI 37-74) at baseline, 48 (95% CI 32-64) at 6 weeks, 43 (95% CI 29-57) at 26 weeks and 40 (95% CI 27-54) at 52 weeks (very low-certainty evidence). The clinical course of disability was slightly more favourable than the clinical course of pain. INTERPRETATION: Participants with acute and subacute low back pain had substantial improvements in levels of pain and disability within the first 6 weeks ( moderate-certainty evidence); however, participants with persistent low back pain had high levels of pain and disability with minimal improvements over time (very low-certainty evidence). Identifying and escalating care in individuals with subacute low back pain who are recovering slowly could be a focus of intervention to reduce the likelihood of transition into persistent low back pain. PROTOCOL REGISTRATION: PROSPERO - CRD42020207442.

The efficacy of loading programmes for improving patient-reported outcomes in chronic midportion Achilles tendinopathy: A systematic review.

OBJECTIVE: Achilles tendinopathy is a common type of overuse condition, with isolated eccentric loading (ECL) programmes being the principal conservative treatment of choice. However, alternative protocols, involving different contraction types, have more recently been investigated. The purpose of the present review was to examine the evidence from studies comparing two or more different types of loading programmes in relation to patient-reported outcomes for people with Achilles tendinopathy. METHODS: A systematic review was undertaken, and the risk of bias of included papers were assessed using the Cochrane Risk of Bias tool. An electronic search of CINAHL, MEDLINE, Embase and SPORTDiscus was undertaken from their inception to May 2018. The eligibility criteria for selecting studies were randomized controlled or clinical controlled trials investigating two or more different loading programmes for chronic (>3 months) Achilles tendinopathy. RESULTS: Seven articles were included in the review. Low-quality evidence exists that a do-as-tolerated modification of the Alfredson programme is more effective than the standardized programme at improving function in the short term. Very-low-quality evidence suggests that ECL is superior at reducing pain levels than concentric in isolation, but no more effective at improving pain or disability than concentric-eccentric programmes. CONCLUSIONS: There is conflicting evidence regarding the superiority of ECL over other contraction types, challenging the current approach to managing Achilles tendinopathy. There is also evidence that do-as-tolerated repetition volumes are more effective at improving function in the short term compared with those recommended by the standardized Alfredson protocol.

The use of posture-correcting shirts for managing musculoskeletal pain is not supported by current evidence - a scoping review of the literature.

BACKGROUND AND AIMS: The concept of bad posture being a dominant driver of pain is commonly held belief in the society. This may explain the significant attention supportive clothing such as posture-correcting shirts has recently gained in Scandinavia and the USA. The aim of this scoping review was to present an overview and synthesis of the available evidence for the use of posture-correcting shirts aimed at reducing pain or postural discomfort and optimising function/posture. METHODS: A systematic search was conducted for literature investigating the effect of posture-correcting shirts on musculoskeletal pain or function. PubMed, Embase, CINAHL, PEDro and the Cochrane Library were searched for relevant literature. Results of the searches were evaluated by two independent reviewers in three separate steps based on title, abstract and full text. For data synthesis, the population, intervention, comparator and outcome were extracted. The quality of the literature was evaluated using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies and the risk of bias was assessed using the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) assessment tool or the RoB 2.0 tool for individually randomized, parallel group trials. The overall confidence in the literature was determined using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: A total of 136 articles were identified and six of these were included in the review. These studies were heterogeneous with regards to aims, outcomes and methods, presenting contrasting results. The overall findings were that posture-correcting shirts change posture and subjectively have a positive effect on discomfort, energy levels and productivity. The quality of the included literature was poor to fair with only one study being of good quality. The risk of bias was serious or critical for the included studies. Overall, this resulted in very low confidence in available evidence. An important limitation of all studies was that they were conducted in pain-free individuals. CONCLUSIONS: The contrasting findings and the low quality of current literature, questions the intended effect of posture-correcting shirts and whether the changes it creates are in fact useful for clinical practice. Moreover, the findings are contrasted by the available evidence regarding posture and pain with a particular focus on whether this management strategy may have a detrimental effect on people living with musculoskeletal pain. A major limitation to the existing literature on the effect of posture-correcting shirts is that no studies have investigated their effect in clinical populations. IMPLICATIONS: Based on the available literature and the major limitation of no studies investigating clinical populations, there is no good quality evidence to support recommendation of posture-correcting shirts as a management strategy for musculoskeletal pain. Promotion of this product may reinforce the inaccurate and unhelpful message that poor posture leads to pain. The efficacy of such garments should be tested in clinical populations and not only in pain-free individuals, to assess whether there is any meaningful benefit of this management approach. Until then, the use of posture-correcting shirts for musculoskeletal pain is not supported by current evidence.

Efficacy of heavy eccentric calf training for treating mid-portion Achilles tendinopathy: a systematic review and meta-analysis.

OBJECTIVE: To assess the effectiveness of heavy eccentric calf training (HECT) in comparison with natural history, traditional physiotherapy, sham interventions or other exercise interventions for improvements in pain and function in mid-portion Achilles tendinopathy. DESIGN: A systematic review and meta-analysis were conducted as per the PRISMA guidelines. DATA SOURCES: PUBMED, CINAHL (Ovid) and CINAHL (EBSCO) were searched from inception until 24 September 2018. ELIGIBILITY CRITERIA: Randomised controlled trials comparing HECT to natural history, sham exercise, traditional physiotherapy and other exercise interventions were included. Primary outcome assessing pain and function was the Victorian Institute of Sports Assessment-Achilles. RESULTS: Seven studies met the inclusion criteria. This review suggests HECT may be superior to both natural history, mean difference (MD) (95% CI) of 20.6 (11.7 to 29.5, one study) and traditional physiotherapy, MD (95% CI) of 17.70 (3.75 to 31.66, two studies). Following removal of one study, at high risk of bias, due to pre-planned sensitivity analysis, this review suggests HECT may be inferior to other exercise interventions, MD (95% CI) of -5.65 (-10.51 to -0.79, three studies). However, this difference is unlikely to be clinically significant. CONCLUSION: Current evidence suggests that HECT may be superior to natural history and traditional physiotherapy while HECT may be inferior to other exercise interventions. However, due to methodological limitations, small sample size and a lack of data we are unable to be confident in the results of the estimate of the effect, as the true effect is likely to be substantially different. SYSTEMATIC REVIEW REGISTRY: PROSPERO registration number: CRD4201804493 PROTOCOL REFERENCE: This protocol has been published open access: Murphy M, Travers MJ, Gibson, W. Is heavy eccentric calf training superior to natural history, sham rehabilitation, traditional physiotherapy and other exercise interventions for pain and function in mid-portion Achilles tendinopathy? Systematic Reviews 2018; 7: 58.

Modulation of Stretch-Shortening-Cycle Behavior With Eccentric Loading of Triceps Surae: A Possible Therapeutic Mechanism.

CONTEXT: Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism. OBJECTIVE: To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task. DESIGN: Within-subjects repeated-measures observational study. SETTING: University motion-analysis laboratory. PARTICIPANTS: Healthy adults. INTERVENTIONS: A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine. MAIN OUTCOME MEASURES: Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system. RESULTS: Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14-44% earlier (P < .001) after the loading intervention. CONCLUSIONS: These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved "buffering" of the tendon by the neuromuscular system.

Achilles tendinopathy alters stretch shortening cycle behaviour during a sub-maximal hopping task.

OBJECTIVES: To describe stretch shortening cycle behaviour of the ankle and lower limb in patients with Achilles tendinopathy (AT) and establish differences with healthy volunteers. DESIGN: Between-subjects case-controlled. METHODS: Fifteen patients with AT (mean age 41.2±12.7 years) and 11 healthy volunteers (CON) (mean age 23.2±6.7 years) performed sub-maximal single-limb hopping on a custom built sledge-jump system. Using 3D motion analysis and surface EMG, temporal kinematic (lower limb stiffness, ankle angle at 80ms pre-contact, ankle angle at contact, peak ankle angle, ankle stretch amplitude) and EMG measures (onset, offset and peak times relative to contact) were captured. Data between AT and CON were compared statistically using a linear mixed model. RESULTS: Patients with AT exhibited significantly increased lower limb stiffness when compared to healthy volunteers (p<0.001) and their hopping range was shifted towards a more dorsiflexed position (p<0.001). Furthermore, ankle stretch amplitude was greater in AT compared with healthy volunteers (p<0.001). A delay in muscle activity was also observed; soleus onset (p<0.001), tibialis anterior peak (p=0.026) and tibialis anterior offset (p<0.001) were all delayed in AT compared with CON. CONCLUSIONS: These findings indicate that patients with AT exhibit altered stretch-shortening cycle behaviour during sub-maximal hopping when compared with healthy volunteers. Patients with AT hop with greater lower limb stiffness, in a greater degree of ankle dorsiflexion and have a greater stretch amplitude. Likewise, delayed muscle activity is evident. These findings have implications in terms of informing the understanding of the pathoaetiology and management of AT.

Stability of lower limb minimal perceptible difference in floor height during hopping stretch-shortening cycles.

This study aimed to investigate a novel proprioceptive test, the minimal perceptible difference (MPD) test, that assessed participants' ability to perceive floor height changes whilst hopping. Sixteen healthy volunteers performed multiple trials of five hops on a custom built sleigh apparatus that permitted a floor height change (range 3 -48 mm) or no change, as dictated by a structured searching algorithm. Minimum detected surface height change was recorded for eight different hopping conditions (factors-technique: alternate/bilateral hopping; side: dominant/non-dominant; direction of change: up/down) over two separate testing occasions. Within day and between day reliability were assessed using intraclass correlation coefficient (ICC) and 95% confidence intervals. The only factor which significantly influenced the sensitivity of subjects to detect changes in floor height was the hopping technique (bilateral or alternate). The mean MPD was significantly lower (p < 0.0001) for the bilateral hopping technique (MPDmean = 15.7 mm) when compared to the alternate hopping technique (MPDmean = 26.6 mm). All bilateral hopping techniques yielded moderate to high ICC for within (0.60-0.79) and between day (0.67-0.88) reliability. The results suggest that the bilateral hopping MPD assessment is a reliable, functional assessment of proprioception sensitivity during repeated stretch-shortening cycles that may better reflect human gait than established static assessment. Increased sensitivity to detection during bilateral hopping may reflect strategy dependent utility of proprioceptive information.