Effect of Massage on Clinical and Physiological Variables During Muscle Fatigue Task in Participants With Chronic Low Back Pain: A Crossover Study.

OBJECTIVE: The purpose of this study was to determine if a reduction of short-term physiological and clinical effects of muscle fatigue can be seen after a session of massage in nonspecific chronic low back pain (cLBP) individuals and to study the possible association between physiological and clinical changes induced by massage. METHODS: Thirty-six cLBP individuals participated in 2 experimental sessions. In one session, the Sorenson protocol was preceded by a 30-minute massage, but in the other session, only the Sorenson test was performed by participants. Lumbar paraspinal muscle activity was recorded using surface electromyography, and maximal voluntary contraction force was measured using a load cell. Participants rated their lumbar pain intensity before and after massage and after the Sorensen protocol. A 2-way repeated-measures analysis of variance was conducted to test the effect of massage on both variables for both conditions. Pearson correlation analyses were conducted to determine the linear association between physiological and clinical responses to massage. RESULTS: Results showed that pain perception was significantly reduced after massage (P = .004) but did not seem to influence pain score increases occurring after the Sorensen protocol. Individuals with a high score of low back pain-related disability showed lower back muscle endurance time (r = -.35). Massage yielded no significant effect on fatigue-related physiological variables. CONCLUSION: The perception of pain in cLBP individuals was reduced after massage. Although massage yielded some positives clinical effects, they were not explained by a reduction in physiological effect of muscle fatigue.

Contribution of Load Expectations to Neuromechanical Adaptations During a Freestyle Lifting Task: A Pilot Study.

OBJECTIVES: The main goal of this study was to determine to what extent load expectations modulate neuromechanical adaptations in individuals with and without chronic low back pain (cLBP) when lifting and lowering various loads. The second goal was to assess the feasibility of a simple lifting protocol during which expectations about loads were manipulated. METHODS: Seventeen participants with cLBP and 18 participants without low back pain were asked to lift and lower boxes of mild to moderate loads. Two kinds of expectations (lighter and heavier) were respectively associated to each experimental block. Self-reported exertion was assessed to control for expectations modulation. Erector spinae and vastus lateralis electromyography (EMG) activity were recorded and kinematics angle calculated. RESULTS: The results showed a main effect of expectations, with loads introduced as heavier being associated to a higher exertion compared with loads introduced as lighter. EMG activity analyses revealed significant interaction involving expectations, movement phase, and loads, as well as significant differences between groups. Kinematic angles did not reveal any significant effect of expectations nor group during the lifting phase. CONCLUSIONS: Psychological factors may contribute to neuromechanical adaptations to low back pain. Our preliminary findings show that expectations about loads may result in neuromechanical differences between individuals with cLBP and those without cLBP. This pilot study showed that testing the manipulation of expectations and EMG records was feasible but highlighted the need to go beyond single infrared markers to assess kinematics.

Musculoskeletal symptoms in an adolescent athlete population: a comparative study.

BACKGROUND: Musculoskeletal pain, symptoms or injuries are prevalent in the adolescent athlete population as well as in the general adolescent population, and often have significant consequences on their future musculoskeletal health. However, differences between these two populations in regards to their musculoskeletal health are not known and have not yet been explored. Therefore, the main objectives of this study are to 1) compare the 6-month prevalence of musculoskeletal symptoms and their impact on school attendance and reduction in sport or leisure activity between a group of adolescent athletes and a group of control adolescents, and 2) determine if gender has different effects on the prevalence of musculoskeletal symptoms in these two populations. METHODS: Among adolescents who participated in the 2012 Québec summer games, 1,865 agreed to participate and constituted the adolescent athletes group (mean age:14.12 ± 1.22). An additional cohort of 707 adolescents from two schools was also recruited to form the comparison control group (mean age: 14.69 ± 1.38). Anthropometric data were collected, and the musculoskeletal 6-month prevalence of symptoms and their related impacts were assessed using the Teen Nordic Musculoskeletal Screening Questionnaire (TNMQ-S). Participants' characteristics as well as symptoms prevalence for the nine anatomical regions as well as their impact on school/work absence and reduction in physical/leisure activities were compared between athletes and control adolescents. RESULTS: When compared to athlete adolescents, significantly more controls had a positive 6-month prevalence of symptoms affecting the neck (48.8% vs 26.3%), upper back (41.3% vs 18.1%) and low back (45.4% vs 35.8%) when compared to athlete. Symptoms affecting the spine led to significantly more school absence and reduction in physical activity in the control group. Controls also showed higher prevalence of shoulder (37.1% vs 28.3%) and wrist/hand (23.8% vs 17.4%) symptoms, while athletes had a higher prevalence of elbow symptoms (8.7% vs 11.4%). CONCLUSION: Despite their higher risk of injuries related to high levels of competition or sport participation, adolescent athletes have fewer symptoms affecting the spine than "typical adolescents", and similar prevalence of symptoms affecting the body's extremities. Further investigations are necessary to understand the differences between athletes and non-athletes in regard to disability and long-term complications associated to musculoskeletal pain or symptoms.

Trunk motor variability in patients with non-specific chronic low back pain.

PURPOSE: To identify and characterize trunk neuromuscular adaptations during muscle fatigue in patients with chronic low back pain (LBP) and healthy participants. METHODS: Forty-six patients with non-specific chronic LBP and 23 healthy controls were asked to perform a trunk muscles fatigue protocol. Surface electromyography was recorded using two adhesive matrix of 64 electrodes applied bilaterally over the erector spinae. Pain score, kinesiophobia and physical disability were analyzed through different questionnaires. To characterize motor variability, dispersion of muscular activity center of gravity was computed. Motor variability between groups was compared using repeated-measures analyses of variance. RESULTS: Score of disability and kinesiophobia were significantly higher in patients with LBP. Results indicated a significant group effect characterized by an increased motor variability in the healthy group through the entire fatigue task on the left (p = 0.003) and right side (p = 0.048). Interestingly, increasing muscle fatigue led to increased motor variability in both groups (on both sides (p < 0.001) but with a greater increase in the healthy group. CONCLUSION: Muscle recruitment is altered in patients with chronic LBP in the presence of muscle fatigue. Consequently, these patients exhibit changes in muscle recruitment pattern and intensity (lower levels of motor variability) during sustained isometric contraction that may be attributed to variation in the control of motor units within and between muscles. However, patients with LBP are able to increase their motor variability over time but with a lower increase compared to healthy participants.

Assessment of musculoskeletal symptoms and their impacts in the adolescent population: adaptation and validation of a questionnaire.

BACKGROUND: Valid and reliable instruments measuring musculoskeletal symptoms prevalence and their impacts in the adolescent population are scarce. The Extended Nordic Musculoskeletal Questionnaire (NMQ-E) is a reliable instrument that measures the prevalence, severity and impact of musculoskeletal symptoms. The purpose of this study was: (1) to develop a musculoskeletal symptom screening tool for younger populations derived from the NMQ-E and NMQ French versions and (2) to assess the validity and reliability of the adapted version of the instrument. METHODS: Based on the results of a translated (French) and adapted NMQ-E administered to 61 adolescents, a final 27-item dichotomous questionnaire was developed. The questionnaire measured the 6-month prevalence of musculoskeletal symptoms and the impact of these symptoms on school attendance as well as on sports and leisure activity participation. Among the adolescents who agreed to participate, thirty-nine (mean age: 13.7 ± 1.8) formed the reliability cohort and thirty-four (mean age: 14.2 ± 2.3) formed the criterion validity cohort. Reliability was measured by test-retest with a mean time interval of 28 hours. Criterion validity was assessed by comparing the answers to the questionnaires to the participants' clinical records. Statistical tests used were proportions of observed agreement (Po) and the Cohen kappa statistic (k). RESULTS: The mean Po for the test-retest was 0.92 for the 6-month symptom prevalence items, 0.99 for the impact of symptoms on school items and 0.96 for the impact on sports and leisure activities items. Kappa values for the reliability assessment ranged between 0.57 and 1.00 for the 27 dichotomous variables. The criterion validity kappa obtained for the agreement between participants' clinical records and questionnaires was k = 0.76. CONCLUSIONS: Kappa values for the reliability and the criterion validity are of moderate to perfect agreement beyond chance, indicating that there are only minor variations between tests, and good agreement between questionnaire items and clinical records. These results indicate that the adapted version of the NMQ-E is an appropriate self-administered musculoskeletal symptom screening tool for the adolescent population. Items related to the impacts of symptoms would benefit from additional validation using school and sport attendance records.

Is performance in goal oriented head movements altered in patients with tension type headache?

BACKGROUND: Head repositioning tasks have been used in different experimental and clinical contexts to quantitatively measure motor control performance. Effects of pain on sensorimotor control have often been described in various musculoskeletal conditions and may provide relevant information with regard to potential mechanisms underlying tension-type headaches. The purpose of the current study was to compare the performance of patients with tension-type headache and healthy participants in a cervical aiming task using the Fitts' task paradigm. METHODS: Patients with tension-type headache and healthy controls were compared in a cervical aiming task. Participants were asked to move their head as quickly, and precisely as possible to a target under various experimental conditions. Dependent variables included movement time, variable error, constant error and absolute error. RESULTS: As predicted by Fitts' law, decreasing target size and increasing head rotation amplitudes yielded longer movement times in both groups. Participants with tension-type headache, when compared to healthy participants showed a significant increase in both constant and absolute errors for each of the four conditions. CONCLUSION: Decreased motor performance was observed in participants with tension-type headache, likely due to altered motor control of the neck musculature. Future research is warranted to investigate the clinical aspect related to decrease in motor performance.

Using a contralateral shoe lift to reduce gait deterioration during an offloading fast-walk setting in diabetic peripheral neuropathy: A comparative feasibility study.

AIMS: Diabetic peripheral neuropathy (DPN) is a predictor of foot ulcers and leads to sedentary behaviour. This comparative study evaluated gait and feasibility of a 20-minute fast walk, at 40-60% of cardiopulmonary capacity, in individuals with DPN wearing an offloading boot and a contralateral shoe balancer. METHODS: Gait parameters were measured with inertial sensors on 32 individuals (group with DPN [n = 16], group with diabetes but without DPN [n = 9], and a group without diabetes/DPN [n = 7]). Feasibility was assessed by feedback on perceived effort and adverse events. Gait outcomes were compared between groups with or without a shoe balancer using one-way ANOVAs. RESULTS: The three groups were equivalent in terms of activity level and age and gender except for the body mass index. Both groups with diabetes exhibited minimal decreased gait speed (p > 0.005) and the DPN group exhibited increased double-support percentage (+4.6%, p = 0.01) while walking with an offloading boot and contralateral shoe balancer. The use of a contralateral shoe balancer reduced gait asymmetry. Lower physical activity level was associated with further gait deterioration in all groups. Few adverse events were reported, and 91% of participants reported that the proposed activity would be feasible daily. CONCLUSIONS: The offloading boot deteriorated gait function, but a contralateral shoe balancer minimized its impact, especially in the context of physical activity in people with diabetes and DPN.

Lower Limb Biomechanics During Drop-Jump Landings on Challenging Surfaces in Individuals With Chronic Ankle Instability.

CONTEXT: Individuals with chronic ankle instability (CAI) exhibit impaired lower limb biomechanics during unilateral drop-jump landings on a flat surface. However, lower limb biomechanical adaptations during unilateral drop-jump landings on more challenging surfaces, such as those that are unstable or inclined, have not been described. OBJECTIVE: To determine how unilateral drop-jump landing surfaces (flat, unstable, and inclined) influence lower limb electromyography, kinematics, and kinetics in individuals with CAI. DESIGN: Descriptive laboratory study. SETTING: Biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 22 young adults (age = 24.9 ± 4.9 years, height = 1.68 ± 0.08 m, mass = 70.6 ± 11.4 kg) with CAI. INTERVENTION(S): Participants completed 5 trials each of unilateral drop-jump landings on a flat surface (DROP), an unstable surface (FOAM), and a laterally inclined surface (WEDGE). MAIN OUTCOME MEASURE(S): Electromyography of the gluteus medius, vastus lateralis, gastrocnemius medialis, peroneus longus, and tibialis anterior muscles was recorded. Ankle and knee angles and moments were calculated using a 3-dimensional motion-analysis system and a force plate. Biomechanical variables were compared among tasks using 1-dimensional statistical nonparametric mapping. RESULTS: During DROP, greater ankle-dorsiflexion and knee-extension moments were observed than during FOAM and WEDGE and greater vastus lateralis muscle activity was observed than during FOAM. Greater ankle-inversion and plantar-flexion angles were noted during FOAM and WEDGE than during DROP. Peroneus longus muscle activity was greater during DROP than during FOAM. During FOAM, greater ankle-inversion and knee-extension angles and ankle-inversion and internal-rotation moments, as well as less peroneus longus muscle activity, were present than during WEDGE. CONCLUSIONS: The greater ankle-inversion and plantar-flexion angles as well as the lack of increased peroneus longus muscle activation during the FOAM and WEDGE conditions could increase the risk of recurrent lateral ankle sprain in individuals with CAI. These findings improve our understanding of the changes in lower limb biomechanics when landing on more challenging surfaces and will help clinicians better target deficits associated with CAI during rehabilitation.

Lower limb biomechanics in individuals with chronic ankle instability during gait: a case-control study.

BACKGROUND: Individuals with chronic ankle instability (CAI) exhibit many biomechanical changes to lower limbs during walking. However, only a few studies have investigated the differences in lower limb biomechanics of individuals with CAI compared to healthy controls using a comprehensive approach including kinematic, kinetic and electromyography (EMG) measures. Consequently, the theoretical framework explaining the biomechanical adaptations in individuals with CAI is mostly based on the results of studies including heterogenous methods and participants' specificities (e.g., level of disability). More studies using a comprehensive approach are needed to better understand the biomechanical adaptations associated with CAI. The objective of this case-control study was to identify the kinematic, kinetic and EMG differences between individuals with CAI and healthy controls during walking. METHODS: Twenty-eight individuals with CAI and 26 healthy controls were recruited to walk at a self-selected speed during which lower limb kinematics, kinetics and EMG were analysed. Ankle and knee angles and moments as well as gluteus medius, vastus lateralis, gastrocnemius lateralis, peroneus longus and tibialis anterior muscles activity were compared between the CAI and control groups using one-dimensional statistical parametric mapping. RESULTS: The CAI group exhibited greater ankle inversion angles from 14 to 48% of the stance phase (%SP) (p = 0.008), ankle eversion moments from 40 to 78%SP (p < 0.001), knee abduction moments from 3 to 6%SP and peroneus longus muscle activity from 0 to 15%SP (p = 0.003) and 60 to 76%SP (p = 0.003) compared to the control group. No significant between-group differences in ankle sagittal and transverse angles and moments, knee angles, knee sagittal and transverse moments as well as gluteus medius, vastus lateralis, gastrocnemius lateralis and tibialis anterior muscles activity were found. CONCLUSIONS: During the first half of the stance phase, individuals with CAI could be at more risk of sustaining recurrent LAS mostly due to greater ankle inversion angles. However, the greater ankle eversion moments and peroneus longus muscle activity during the second half of the stance phase were an efficient mechanism to correct this maladaptive gait pattern and allowed to attenuate the faulty ankle movements during the pre-swing phase.

Biomechanical effects of foot orthoses with and without a lateral bar in individuals with cavus feet during comfortable and fast walking.

BACKGROUND/PURPOSE: The biomechanical effects of foot orthoses (FOs) with and without a lateral bar compared to a control condition during walking at different speeds are still unknown. The objective of this study was to compare the biomechanical effects of functional FOs with and without a lateral bar to a control condition during comfortable walking in individuals with cavus feet and determine if their effects change at a fast speed. METHODS: Fifteen individuals with cavus feet (age: 25.3 ± 5.8 yrs) walked under two experimental conditions (FOs with and without a lateral bar) and a control condition (shoes only) at comfortable (CW) and fast (FW) speeds. The outcome measures were ankle and knee angles and gluteus medius, vastus lateralis, gastrocnemius lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior electromyography (EMG) amplitudes during the stance phase of walking and were compared between the FOs and a control condition using one-dimensional statistical parametric mapping. RESULTS: During CW, both FOs decreased ankle dorsiflexion and increased knee extension angles compared to no FOs. FOs with a lateral bar also decreased peroneus longus EMG amplitudes. During FW, FOs with and without a lateral bar decreased ankle dorsiflexion angles compared to no FOs. CONCLUSION: Both types of FOs had different effects on the biomechanics of the lower limb compared to a control condition. The decreased peroneus longus EMG amplitudes during CW in individuals with cavus feet could have important clinical implications in other populations, such as individuals with painful cavus feet. The orthoses only affected the ankle dorsiflexion angles at a fast speed and no EMG amplitude or knee kinematics effects were observed. Further studies assessing the ankle kinematics and kinetics effects of these orthoses are needed to improve our understanding of their mechanism of action and inform future efficacy trials.

Effectiveness of saline water and lidocaine injection treatment of intractable plantar keratoma: a randomised feasibility study.

BACKGROUND: An intractable plantar keratoma (IPK) is a conical thickening of the epidermis' stratum corneum and a common cause of foot pain which can have a significant, detrimental impact on the mobility, quality of life and independence of individuals. Conservative treatments are currently offered to patients with IPK, but they are unsatisfactory since they do not offer a sufficient or permanent reduction of symptoms. The purpose of this study was the evaluation of the feasibility, safety and effectiveness of innovative treatments for intractable plantar keratoma (IPK). METHODS: A randomized single blind trial with 40 patients divided with block randomization in four parallel groups was conducted to compare treatment combinations: conservative sharp debridement only or sharp debridement with needle insertion, physiological water injection or lidocaine injection. All patients obtained the same treatment four times at a four-week interval. At each visit, visual analog scale (VAS), Foot Function Index (FFI) and IPK size were evaluated. VAS and FFI were also completed at a six and twelve-month follow-up. RESULTS: Our findings in regards to feasibility demonstrated recruitment challenges because of the anticipated pain that would be provoked by needle insertion may not be worth the potential pain relief compared to debridement alone from the patient's perspective. This was also the principal cause of drop out. Our preliminary results show no main effect of group for any of the clinical outcomes: pain felt on VAS, FFI score, IPK's size (p > 0.05). However, the analysis revealed a statistically significant effect of time on VAS (p < 0.001), FFI score (p < 0.001) and IPK's size (width and depth (p < 0.001); length (p = 0.001)), but no group x time interaction was found (p > 0.05). CONCLUSIONS: This study demonstrates that IPK treatment consisting of sharp debridement with needle insertion, physiological saline water injection or lidocaine injection is feasible and safe. There was a non-statistically significant trend toward diminishing pain intensity compared to scalpel debridement alone. The pain provoked by needle insertion and injection treatments must be addressed with a scientifically proven protocol to make it more comfortable for patients before these treatments could be considered in further studies. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04777227 . 2 March, 2021 - Retrospectively registered (All participants were recruited prior to registration).

Effectiveness of an exercise-based prehabilitation program for patients awaiting surgery for lumbar spinal stenosis: a randomized clinical trial.

Lumbar spinal stenosis is the most common reason for spine surgery in older adults, but the effects of prehabilitation on perioperative outcomes among these patients have not been investigated. This study aims to evaluate the effectiveness of a preoperative exercise-based intervention program compared with usual care on the improvement of clinical status, physical capacities and postoperative recovery of patients awaiting surgery for lumbar spinal stenosis. Sixty-eight participants were randomised to receive either a 6-week supervised exercise-based prehabilitation program or hospital usual care. The outcomes included both clinical and physical measures. Data collection occurred at post-intervention, and 6 weeks, 3- and 6-months post-surgery. Significant but small improvements were found in favour of the experimental group at the post-intervention assessment for pain intensity, lumbar spinal stenosis-related disability, lumbar strength in flexion, low back extensor muscles endurance, total ambulation time, and sit to stand performance. A significant difference in favor of the intervention group was found starting at the 3-month postoperative follow-up for low back-related disability. No adverse events were reported. Exercise-based prehabilitation did not improve short-term postoperative recovery in patients with lumbar spinal stenosis.

Impact of load expectations on neuromuscular and postural strategies during a freestyle lifting task in individuals with and without chronic low back pain.

OBJECTIVE: This study aimed to investigate how load expectations modulate neuromuscular and postural strategies in the anticipation of a freestyle lifting task with varying expected loads in individuals with and without chronic low back pain (cLBP). METHODS: Forty-seven participants, 28 with cLBP pain and 19 without, were recruited and completed a series of freestyle lifting trials (3 sets of box lifted for a total of 36 lifts). Verbal cues were used to modulate their expectations about the boxes' weight: no expectation, lighter or heavier load expectations. Following each set, participants rated their perceived exertion on a visual analog scale. During the lifting protocol, kinematics (time to maximal flexion, angular velocity and joint angles), electromyography muscle activity (erector spinae and quadriceps) and center of pressure displacement were simultaneously recorded. RESULTS: Results showed that time to maximal knee flexion was modulated by load expectations in both groups (mean lighter load expectations = 1.15 ± 0.32 sec.; mean heavier load expectations = 1.06 ± 0.31 sec.). Results also showed a load expectations X group interaction for that time to maximal hip and lumbar flexion. Time to maximal hip flexion decreased with heavier load expectations (mean lighter load expectations = 1.20 ± 0.36; mean heavier load expectations = 1.16 ± 0.33) for cLBP only. Time to maximal lumbar flexion increased with heavier load expectation (mean lighter load expectations = 1.41 ± 0.27 sec.; mean lighter load expectations = 1.46 ± 0.29 sec.) for participants without LBP. However, no difference in lumbar, hip nor knee angles were observed between groups or conditions. Results highlighted significant load expectation effects for erector spinae electromyography activity, as lower muscle activations was observed for both groups with heavier load expectations (mean = 0.32 ± 0.15), compared to lighter load expectations (mean = 0.52 ± 0.27). Force plates analyses did not reveal any significant load expectation effects. CONCLUSION: Present findings showed that load expectations modulate movement strategies and muscle activation similarly but not identically in individuals with chronic low back pain and healthy adults during freestyle lifting. Results of the present study partially differ from previous studies and suggest only minor differences in lifting strategies between healthy individuals and individuals with cLBP experiencing low level of pain and disability. More studies are needed to investigate the potential role of load expectations in the development and persistence of chronic low back pain.

Changes in the flexion-relaxation response induced by hip extensor and erector spinae muscle fatigue.

BACKGROUND: The flexion-relaxation phenomenon (FRP) is defined by reduced lumbar erector spinae (ES) muscle myoelectric activity during full trunk flexion. The objectives of this study were to quantify the effect of hip and back extensor muscle fatigue on FRP parameters and lumbopelvic kinematics. METHODS: Twenty-seven healthy adults performed flexion-extension tasks under 4 different experimental conditions: no fatigue/no load, no fatigue/load, fatigue/no load, and fatigue/load. Total flexion angle corresponding to the onset and cessation of myoelectric silence, hip flexion angle, lumbar flexion angle and maximal trunk flexion angle were compared across different experimental conditions by 2 x 2 (Load x Fatigue) repeated-measures ANOVA. RESULTS: The angle corresponding to the ES onset of myoelectric silence was reduced after the fatigue task, and loading the spine decreased the lumbar contribution to motion compared to the hip during both flexion and extension. A relative increment of lumbar spine motion compared to pelvic motion was also observed in fatigue conditions. CONCLUSIONS: Previous results suggested that ES muscles, in a state of fatigue, are unable to provide sufficient segmental stabilization. The present findings indicate that, changes in lumbar-stabilizing mechanisms in the presence of muscle fatigue seem to be caused by modulation of lumbopelvic kinematics.

Load and speed effects on the cervical flexion relaxation phenomenon.

BACKGROUND: The flexion relaxation phenomenon (FRP) represents a well-studied neuromuscular response that occurs in the lumbar and cervical spine. However, the cervical spine FRP has not been investigated extensively, and the speed of movement and loading effects remains to be characterized. The objectives of the present study were to evaluate the influence of load and speed on cervical FRP electromyographic (EMG) and kinematic parameters and to assess the measurement of cervical FRP kinematic and EMG parameter repeatability. METHODS: Eighteen healthy adults (6 women and 12 men), aged 20 to 39 years, participated in this study. They undertook 2 sessions in which they had to perform a standardized cervical flexion/extension movement in 3 phases: complete cervical flexion; the static period in complete cervical flexion; and extension with return to the initial position. Two different rhythm conditions and 3 different loading conditions were applied to assess load and speed effects. Kinematic and EMG data were collected, and dependent variables included angles corresponding to the onset and cessation of myoelectric silence as well as the root mean square (RMS) values of EMG signals. Repeatability was examined in the first session and between the 2 sessions. RESULTS: Statistical analyses revealed a significant load effect (P < 0.001). An augmented load led to increased FRP onset and cessation angles. No load x speed interaction effect was detected in the kinematics data. A significant load effect (P < 0.001) was observed on RMS values in all phases of movement, while a significant speed effect (P < 0.001) could be seen only during the extension phase. Load x speed interaction effect was noted in the extension phase, where higher loads and faster rhythm generated significantly greater muscle activation. Intra-session and inter-session repeatability was good for the EMG and kinematic parameters. CONCLUSIONS: The load increase evoked augmented FRP onset and cessation angles as well as heightened muscle activation. Such increments may reflect the need to enhance spinal stability under loading conditions. The kinematic and EMG parameters showed promising repeatability. Further studies are needed to assess kinematic and EMG differences between healthy subjects and patients with neck pain.

Kinematic, kinetic and electromyographic differences between young adults with and without chronic ankle instability during walking.

The objective of this study was to quantify the kinematic, kinetic and electromyography differences between individuals with and without chronic ankle instability (CAI) during comfortable (CW) and fast (FW) walking. Twenty-one individuals with CAI and 21 healthy controls were recruited to walk at CW and FW speeds. The dependent variables were gluteus medius, vastus lateralis, gastrocnemius lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles mean activity, ankle and knee angles and moments. Kinematic, kinetic and electromyography variables were compared between groups with a one-dimensional statistical non-parametric mapping analysis. The CAI group exhibited no significant difference for ankle angles and moments compared to the control group. However, the CAI group showed less external knee rotation from 56 to 100% (CW) and 51 to 98% (FW) and more knee abduction moment from 1 to 6% and 7 to 9% (CW) and 1 to 2% (FW) of the stance phase. Less gluteus medius muscle activity was also observed from 6 to 9% and 99 to 100% (CW) of the stance phase for the CAI group. These results suggest proximal biomechanical compensations and will help better understand the underlying deficits associated with CAI. They also indicate that regardless of walking speeds, individuals with CAI exhibit similar differences compared to healthy participants.

Unilateral jump landing neuromechanics of individuals with chronic ankle instability.

OBJECTIVES: To assess the neuromechanical (kinematic, kinetic and electromyographic (EMG)) differences between individuals with and without chronic ankle instability (CAI) during unilateral jump landing. DESIGN: Case-control study. METHODS: Kinematic, kinetic and EMG data of 32 participants with CAI and 31 control participants were collected during unilateral side jump landing (SIDE) and unilateral drop landing on three surfaces (even (DROP), unstable (FOAM) and laterally inclined (WEDGE)). Each participant had to complete five trials of each task in a randomised sequence. To compare the neuromechanical differences between groups, a one-dimensional statistical non-parametric mapping analysis was performed. RESULTS: Compared to the control group, the CAI group exhibited increased biceps femoris muscle activity during the preactivation and landing phases, decreased gluteus medius and peroneus longus muscles activity during the preactivation phase and increased knee extension moment during the landing phase of the WEDGE task. The CAI group also exhibited increased ankle dorsiflexion during the landing phase of the FOAM task and decreased vastus lateralis muscle activity during the preactivation phase of the DROP task. Finally, the CAI group exhibited decreased biceps femoris muscle activity during the preactivation and landing phases and decreased gluteus medius muscle activity during the preactivation phase of the SIDE task compared to the control group. CONCLUSIONS: Individuals with CAI present neuromechanical differences during unilateral jump landing compared to healthy individuals. The results of this study will improve our understanding of underlying deficits associated with CAI and will help researchers and clinicians to better target them during rehabilitation.

The influence of footwear on walking biomechanics in individuals with chronic ankle instability.

BACKGROUND/PURPOSE: The effects of footwear on the walking kinematics, kinetics and electromyography (EMG) of individuals with chronic ankle instability (CAI) at different speeds are still unknown. The objective of this cross-sectional study was to evaluate the kinematic, kinetic and electromyography differences between shod and barefoot walking at comfortable (CW) and fast (FW) speeds in individuals with CAI. METHODS: Twenty-one individuals with CAI walked on a 5-meter walkway shod and barefoot at CW and FW speeds. A force plate was used to record the ground reaction forces, a 3-D motion analysis system to record the lower limb kinematics and a surface EMG system to collect the gluteus medius, vastus lateralis, gastrocnemius lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles activity. The dependent variables were ankle and knee angles and moments and normalized muscle activity. The shod and barefoot data during CW and FW were compared using a one-dimensional non-parametric mapping analysis. RESULTS: The main results of this study were that individuals with CAI exhibited more ankle dorsiflexion angle, knee extension and tibialis anterior muscle activation during the beginning of the stance phase during shod compared to barefoot walking. Also, the biomechanical effects of shoes are similar during walking at FW and CW. CONCLUSION: The biomechanical deficits associated with CAI were partly attenuated during the shod compared to the barefoot condition and these effects were similar at CW and FW. These findings are compatible with the concept that locomotor interventions using suitable shoes may enhance gait abilities in individuals with CAI.

Effects of foot orthoses on walking and jump landing biomechanics of individuals with chronic ankle instability.

OBJECTIVES: To evaluate the kinematic, kinetic and electromyographic (EMG) immediate effects of foot orthoses (FOs) during walking, maximal single-leg side jump landing (SIDE) and unilateral drop landing on even (DROP), inclined and unstable (FOAM) surfaces in individuals with chronic ankle instability (CAI). DESIGN: Cohort study. SETTING: Biomechanics laboratory. PARTICIPANTS: 26 healthy individuals with CAI. MAIN OUTCOME MEASURES: Ankle and knee angles/moments and lower-limb EMG of the gluteus medius, vastus medialis, vastus lateralis, biceps femoris, gastrocnemis medialis, gastrocnemius lateralis, peroneus longus and tibialis anterior muscles. RESULTS: The main results are that with FOs, individuals with CAI exhibited decreased tibialis anterior muscle activity from 19 to 38% and 39-99% of the landing phase during the DROP task. They also exhibited increased biceps femoris muscle activity from 56 to 65% of the preactivation phase during walking. No significant ankle and knee joints angles and moments difference was observed when wearing FOs in any of the experimental tasks. CONCLUSIONS: The results of this study suggest that the biomechanical effects of FOs are task-dependent and only affect EMG activity. They will help clinicians and researchers to better understand FOs' role in treatment and prevention of CAI.

Feasibility of conducting an active exercise prehabilitation program in patients awaiting spinal stenosis surgery: a randomized pilot study.

Prehabilitation is defined as the process of augmenting functional capacity before surgery in preparation for the postoperative phase. This study intends to assess the feasibility of conducting a preoperative intervention program in patients with lumbar spinal stenosis and to report on the piloting of the proposed intervention. Patients were allocated to a 6-week supervised preoperative rehabilitation program or a control group. The intervention included supervised exercise sessions aimed to improve strength, muscular endurance, and spinal stabilization. Outcomes were measured at baseline, 6 weeks later and again 6 weeks, 3 months and 6 months after surgery. Sixty-five percent of admissible participants agreed to take part in the study, of which 5% dropped out before the end of the intervention period. Eighty-eight percent of potential training sessions were delivered without adverse event. Improvements were seen in favour of the experimental group at the preoperative assessment for active ranges of motion, leg pain intensity, lumbar extensor muscle endurance and walking capacities. Results show that slight modifications to the choice of outcome measures would increase feasibility of the main study. The absence of adverse events coupled with positive changes seen in dependant outcome measures warrant the conduct of a full-scale trial assessing the effectiveness of the intervention.