Regional and widespread pain sensitivity decreases following stretching in both men and women - Indications of stretch-induced hypoalgesia.

INTRODUCTION: This study aimed to investigate the effect of sex on regional and widespread pain sensitivity following acute bouts of stretching and to investigate the acute effect of stretching on regional and widespread pain sensitivity following stretching. METHODS: 73 healthy adults (36 females; mean age 25.6 ± 6.7 years) with an age range from 19 to 62 years were recruited for this experimental study. Regional and distant pain pressure pain thresholds, passive knee extension range of motion and passive resistive torque were measured before and 30 s after four bouts of 30-s static muscle stretching of the knee flexors with 20-s rest between bouts. RESULTS: No significant sex differences were found for pressure pain thresholds (p > 0.132), range of motion (p = 0.446) or passive resistive torque (p = 0.559) between pre-stretch and post-stretch measures. There were significant increases in pressure pain thresholds (p = 0.010), range of motion (p = 0.001) and passive resistive torque (p = 0.007) between pre-stretch and post-stretch measures. CONCLUSION: Muscle stretching significantly decreased regional and widespread pain sensitivity, indicating that central pain-modulating mechanisms are engaged during muscle stretching, resulting in stretch-induced hypoalgesia. Moreover, the results showed that the effect of stretching on regional and widespread pain sensitivity is not sex-specific.

Moving together - benefits of an online dance program on physical and mental health for older women: an exploratory mixed-method study.

BACKGROUND: Previous studies show that in-person dance training is a beneficial form of physical activity that involves mental, social, and physical dimensions. This exploratory study investigated the benefits of a 12-week online dance training intervention on mental and physical health outcomes for older women. METHODS: A convergent parallel mixed-method design was used. Forty-five older adults (74.0 ± 5.3 yrs old, 44 women) were recruited through advertisements at activity and rehabilitation centers in the North Denmark region. The intervention consisted of two weekly 60-min classes of improvisation and salsa delivered online through video call applications. Changes in physical health outcomes (body mass and composition, resting blood pressure, Senior Fitness Test battery) and self-rated health and wellbeing (health-related quality of life (HRQOL), feelings of loneliness) were assessed prior to and after 12 weeks of dancing. Focus group interviews were conducted post-intervention to further explore the benefits as well as the participant's experience of the intervention. Thematic analysis of the qualitative data was conducted. RESULTS: Thirty-two participants (all women) completed the study. Significant improvements in fitness were found for the number of arm curls performed (baseline: 12.3 ± 3.0; post-intervention: 13.7 ± 3.0, P = 0.005), 2-min step test performance (baseline: 66.5 ± 20.0 reps.; post-intervention: 73.8 ± 22.6 reps., P = 0.016), and chair sit-and-reach (baseline: 0.4 ± 11.3 cm; post-intervention: 5.5 ± 10.1 cm, P < 0.001). There was a significant increase in body mass from baseline to post-intervention (P < 0.015). The themes from the focus groups included (1) Participation, (2) Challenges, (3) Progression, (4) Motivation, (5) Perceived health and wellbeing, and (6) Online dance instruction. No significant changes were reported in HRQOL and loneliness from the quantitative data, although the qualitative data did reveal improved feelings of physical health and wellbeing. CONCLUSIONS: The intervention improved several aspects of fitness in older women and improved the participants' perceptions of their own physical abilities and wellbeing. While most participants found the online intervention enjoyable, several participants missed the feedback from the instructors that naturally occurs with in-person instruction.

Assessing standing balance with MOTI: a validation study.

OBJECTIVES: This study aimed to determine the validity and reliability of a new device called MOTI for measuring balance by comparing its performance that with of the gold-standard force platform. METHODS: The study involved collecting data from both devices in dual- and single-leg standing positions with eyes open and closed and using statistical measures to compare their performance. RESULTS: The results showed that MOTI can accurately measure balance during dual-leg standing tasks but has poor to moderate performance during single-leg standing tasks. However, it could detect small changes in postural sway caused by a reduced base of support and/or visual feedback. The study also found that the test-retest reliability was poor to moderate for both devices. CONCLUSIONS: These findings suggest that MOTI has potential as a reliable tool for measuring balance during certain tasks, but further research is needed to improve its performance during single-leg standing. This study provides valuable insights into the validity and reliability of MOTI for measuring balance and highlights the need for further investigation.

Validity of an inertial measurement unit for the assessment of range and quality of movement during head and thoracic spine movements.

BACKGROUND: Patients with spinal pain often exhibit movement limitations and altered motor control, which can be challenging to measure accurately in clinical practice. Inertial measurement sensors present a promising new opportunity to develop valid, low-cost, and easy-to-use methods for assessing and monitoring spinal motion in a clinical setting. AIM: This study aimed to investigate the agreement of an inertial sensor and a 3D camera system for assessing the range of motion (ROM) and quality of movement (QOM) in head and trunk single-plane movements. METHODS: Thirty-three healthy, pain-free volunteers were included. Each participant performed movements of the head (cervical flexion, extension, and lateral flexion) and trunk (trunk flexion, extension, rotation, and lateral flexion), which were simultaneously recorded by a 3D camera system and an inertial measurement unit (MOTI, Aalborg, Denmark). Agreement and consistency were analyzed for ROM and QOM by determining intraclass correlation coefficients (ICC), mean bias, and with Bland-Altman plots. RESULTS: The agreement between systems was excellent for all movements (ICC between 0.91 and 1.00) for ROM and good to excellent for the QOM (ICC between 0.84 and 0.95). The mean bias for all movements (0.1-0.8°) was below the minimum acceptable difference between devices. The Bland-Altman plot indicated that MOTI systematically measured a slightly greater ROM and QOM than the 3D camera system for all neck and trunk movements. CONCLUSION: This study showed that MOTI is a feasible and potentially applicable option to assess ROM and QOM for head and trunk movements in experimental and clinical settings.

Cross-cultural translation and adaptation of the Danish version of the brief version of the 10-item Big Five Inventory.

BACKGROUND: Personality traits are associated with pain-related beliefs and coping strategies, and different chronic conditions are linked through specific personality profiles. This highlights the importance of having valid and reliable measures of personality traits for use in clinical and research settings when assessing patients in chronic pain. PURPOSE: To translate and cross-culturally adapt the 10-item Big Five Inventory (BFI-10) into Danish. METHODS: A bilingual expert panel (N = 4) and a panel of laymen (N = 8) translated and culturally adapted the questionnaire into Danish. Face validity was evaluated in a group of persons suffering from recurring or ongoing painful conditions (N = 9). Data were collected to evaluate the internal consistency, test-retest reliability and factor structure (N = 96). RESULTS: Some of the participants in the lay panel considered the questionnaire too short, considering its aim of assessing personality. Acceptable internal consistency was found for two out of five subscales (0.78 for both Extraversion and Neuroticism), while the internal consistency was non-acceptable for the remaining subscales (0.17-0.45). Test-retest reliability was acceptable for three subscales (0.80 for Neuroticism, 0.84 for Conscientiousness, and 0.85 for Extraversion). Assumptions for determining the factor structure were not met and therefore was this analysis omitted. DISCUSSION: Although face valid, only two out of five subscales had acceptable internal consistency and only three subscales had acceptable test-retest reliability. These findings indicate that interpreting findings regarding personality using the Danish BFI-10 should be done with caution.

Prolonged slumped sitting causes neck pain and increased axioscapular muscle activity during a computer task in healthy participants - A randomized crossover study.

INTRODUCTION: Sitting posture may contribute to spinal pain. Effects of postures on pain, sensitivity and muscle activity during computer tasks were investigated. METHODS: Twenty-five healthy participants, seated at a workstation without backrest, completed four, 15-min typing tasks: A)Upright with forearm-support; B)Upright without forearm-support; C)Slumped with forearm-support; D)Slumped without forearm-support. Participants rated pain every minute on a numerical rating scale (NRS). RMS-EMG was recorded from upper/lower trapezius (UT, LT), serratus anterior and anterior/middle deltoid. At baseline and after tasks, pressure pain thresholds (PPTs) were recorded bilaterally over the head, UT, and leg. RESULTS: All tasks caused clinically relevant increased NRS (≥2/10) compared to baseline (P < 0.001). NRS was higher in Task-D (P < 0.003) and lower in Task-B (P < 0.005) than others. PPTs did not change from baseline. Task-D caused higher UT and LT RMS-EMG (P < 0.02) than other tasks. CONCLUSION: A 15-min task caused pain irrespective of posture with some causing larger changes than others.

Change in functional biomechanics following a targeted exercise intervention in patients with acetabular retroversion and femoroacetabular impingement syndrome.

BACKGROUND: Acetabular retroversion is a form of hip dysplasia that may cause femoroacetabular impingement syndrome (FAIS), leading to pain and restricted hip range of motion. An exercise intervention aiming at altering pelvis tilt and related functional biomechanics may be a useful first-line intervention for patients who are not eligible for surgical repositioning. RESEARCH QUESTION: Does squat and gait biomechanics change following an 8-week targeted exercise program in individuals with symptomatic acetabular retroversion and FAIS? METHODS: This prospective intervention study used participants as their own controls. Examinations were conducted at three time-points: T1 baseline; T2 following an 8-week control period; T3 after 8 weeks' intervention. At each time-point, three-dimensional motion analysis of a deep squat and level gait was performed, and pain intensity was recorded using a numerical rating scale (NRS 0-10). The intervention consisted of a home-exercise program to improve core stability and pelvic movement. Differences in waveforms between time-points across pelvis and lower-limb biomechanics were evaluated using statistical parametric mapping. Delta (Δ, differences between T1-T2 and T2-T3) was used to evaluate changes in spatiotemporal gait parameters and pain. RESULTS: Nineteen patients (18 females), mean age 22.6 (SD 4.5) years, BMI (kg/m2) 23.0 (SD 4.1), were included. Changes (Δ T1-T2 vs. Δ T2-T3) in squat biomechanics were observed as: (i) decreased anterior pelvic tilt, (ii) deeper vertical pelvis position, and (iii) increased knee flexion angle. Contrary, no significant changes in gait biomechanics, Δ walking speed, Δ step length, or NRS for pain were found. SIGNIFICANCE: Following a targeted exercise intervention, participants were able to squat deeper, potentially allowing better hip function. The deepened squat position was accompanied by increased knee flexion and reduced anterior pelvic tilt. Gait biomechanics and patient-reported pain remained unchanged post-intervention. These findings are important for future design of exercise interventions targeting pelvic tilt in symptomatic individuals.

The impact of prolonged experimental neck pain on walking stability and gait kinematics - A parallel-group study.

BACKGROUND: Neck pain is a common problem in the general population, and movement adaptations are a natural response to pain. Previous studies have reported reduced trunk rotation during walking in those suffering from clinical neck pain. However, it is unknown how soon after the onset of pain, movement adaptations are adopted. This study investigated the effect of prolonged experimental neck pain four days after pain onset on gait kinematics during walking. METHODS: Forty healthy participants were randomized to receive injections of nerve-growth-factor or a control injection of isotonic saline into the right splenius capitis muscle at the end of days 0 and 2. Participants performed two walking tasks, walking and walking while reading on a smartphone, on days 0, 4, and 15. Gait kinematics, spatiotemporal parameters, and gait stability were measured using Xsens Awinda. FINDINGS: The nerve-growth-factor group reported increased neck pain intensity (median VAS 17.5 [IQR: 2.75-25.75]) on day 4 compared to day 0 and day 15. No pain intensity changes between days were reported for the isotonic-group. For gait kinematics, a main effect of the task was identified, showing that during the smartphone condition, participants had shorter stride lengths and reduced RoM for the trunk, hip, knee, and ankle compared to normal waking (P < 0.006). INTERPRETATION: Walking while reading on a smartphone, but not mild neck muscle pain, caused changes in the gait kinematics compared to normal walking without neck pain. This finding suggests that movement alterations during walking are not an early feature of prolonged experimental neck pain.

Impaired postural control in diabetes-a predictor of falls?

New evidence points toward that impaired postural control judged by center of pressure measures during quiet stance is a predictor of falls in people with type 1 and type 2 diabetes-even in occurrence of well-known risk factors for falls. INTRODUCTION/AIM: People with type 1 diabetes (T1D) and type 2 diabetes (T2D) are at risk of falling, but the association with impaired postural control is unclear. Therefore, the aim was to investigate postural control by measuring the center of pressure (CoP) during quiet standing and to estimate the prevalence ratio (PR) of falls and the fear of falling among people with diabetes compared to controls. METHODS: In a cross-sectional study, participants with T1D (n = 111) and T2D (n = 106) and controls without diabetes (n = 328) were included. Study procedures consisted of handgrip strength (HGS), vibration perception threshold (VPT), orthostatism, visual acuity, and postural control during quiet stance measured by CoPArea (degree of body sway) and CoPVelocity (speed of the body sway) with "eyes open," "eyes closed" in combination with executive function tasks. A history of previous falls and fear of falling was collected by a questionnaire. CoPArea and CoPVelocity measurements were analyzed by using a multiple linear regression model. The PR of falls and the fear of falling were estimated by a Poisson regression model. Age, sex, BMI, previous falls, alcohol use, drug, HGS, VPT, orthostatism, episodes of hypoglycemia, and visual acuity were covariates in multiple adjusted analyses. RESULTS: Significantly larger mean CoPArea measures were observed for participants with T1D (p = 0.022) and T2D (0.002), whereas mean CoPVelocity measures were only increased in participants with T2D (p = 0.027) vs. controls. Additionally, T1D and T2D participants had higher PRs for falls (p = 0.044, p = 0.014) and fear of falling (p = 0.006, p < 0.001) in the crude analyses, but the PRs reduced significantly when adjusted for mean CoPArea and mean CoPVelocity, respectively. Furthermore, multiple adjusted PRs were significantly higher than crude the analyses.    CONCLUSION: Impaired postural control during quiet stance was seen in T1D and T2D compared with controls even in the occurrence of well-known risk factors. and correlated well with a higher prevalence of falls.

A 3-Dimensional Gait Analysis of the Effects of Fatigue-Induced Reduced Foot Adductor Muscle Strength on the Walking of Healthy Subjects.

Dysfunction of the tibialis posterior muscle is the most common cause of adult acquired flat foot. Tibialis posterior muscle weakness has been observed in several patient populations, including those in the early stages of rheumatoid arthritis. However, the influence of tibialis posterior weakness on gait mechanics is not fully understood, although gait instability has been reported. In 24 healthy participants, 3-dimension lower limb kinematics and kinetics during walking were evaluated bilaterally, before and after, a muscle fatigue protocol aiming to decrease the right foot adductor muscles strength, including the tibialis posterior muscle. The 3-dimension gait kinematics and kinetics were analyzed with statistical parametric mapping. The stance phase duration was increased for the right side. The right ankle external rotation moment decreased, and the left hip extension moment increased with reduced muscle strength compared with normal strength conditions. These changes are similar in patients with dysfunction in the tibialis posterior muscle, indicating that compensatory strategies observed in these patients might be related to the loss of tibialis posterior muscle strength. Such strategies may involve the unaffected side.

The effect of foot orthoses on gait biomechanics and pain among people with rheumatoid arthritis: A quasi-experimental study.

BACKGROUND: Foot pain is frequent among people with rheumatoid arthritis (RA). Foot orthoses (FO) are commonly prescribed with the intention to reduce pain symptoms and improve function. RESEARCH QUESTION: How do a custom-made FO affect pain, gait biomechanics and daily activity among people with RA? METHODS: Twenty-five participants with RA and foot pain completed this quasi-experimental study using a control insole for four weeks and then a custom-made FO in the following four weeks. The foot orthoses were customized by plantar foot shape targeting optimal restoration of normal arch height. A visual analog scale was used to monitor changes in ankle/foot, knee, hip joints, and global arthritis pain. In addition, the perceived pain area was measured using a body chart analysis. Kinematics and kinetics of the hip, knee and ankle joints during gait were analyzed using 3D-motion capture. Daily steps were measured with a wrist-based activity tracker for both the control insole and custom-made FO period, respectively. RESULTS: In comparison to the control insole, the custom-made FO reduced ankle/foot pain intensity (p < 0.001) in addition to a reduction of the perceived pain areas in the feet (p < 0.001), legs (p = 0.012), as well as the arms and hands (p = 0.014). Ankle plantar flexion and eversion moments were also reduced (p < 0.001). No difference in daily steps was observed between the two periods (p = 0.657). SIGNIFICANCE: This study has demonstrated an ankle/foot pain-relieving effect in conjunction with alterations of the ankle joint moments in people with RA using custom-made FO. The pain relief is plausibly attributed to alterations of the ankle joint moments when using the custom-made FO. However, future studies are needed to explore further into therapeutic implication of custom-made FO in pain management of people with RA.

Different types of foot orthoses effect on gait mechanics in patients with rheumatoid arthritis.

Foot orthoses are a first line conservative treatment for foot impairments in patients with rheumatoid arthritis (RA), however their effect on gait mechanics is poorly understood. We aimed to compare changes in lower limb and foot mechanics between two types of commonly used foot orthoses (FO) with a control. Twenty-seven patients with rheumatoid arthritis participated in this crossover study. Two different types of FO (a medially wedged custom-made FO and a prefabricated FO with a metatarsal dome, respectively), were compared against a control insole. During gait, lower limb mechanics were analyzed using 3D motion capture, force plates, and an in-shoe pressure system. Inverse dynamics models were created in the Anybody Modeling System to calculate joint angles and joint moments during gait. Gait variables were analyzed using statistical parametric mapping. Compared to the control, the prefabricated FO had limited effect on gait mechanics. Compared to the control the custom-made FO reduced ankle plantarflexion moment with 0.4 %body weight * body height (BW * BH) between 66 and 76% of stance and ankle eversion moment was reduced 0.16% BW*BH between 3 and 40% of stance. Furthermore, it also reduced the average forefoot plantar pressure by 9 kPa between 20 and 62% of stance compared to the control. Changes in foot pressure distribution, joint moments and angles were most pronounced for custom-made FO compared to the prefabricated FO. The findings suggest that patients with RA and foot impairments may benefit more from an individualized FO strategy, if the aim of the treatment is to alter gait mechanics. (NCT03561688).

Dancing Against falls iN Community-dwElling older adults (DANCE): a study protocol of a stratified, block-randomised trial.

BACKGROUND: Unintentional falls among older adults are of primary importance due to their impact on quality of life. Falling accounts for 95% of hip fractures, leading to an approximately six times increased risk of death within the first 3 months. Furthermore, physical and cognitive parameters are risk factors for falls. The purpose of this study is to examine the effect of a 6-month salsa dance training intervention, compared with regular fitness circuit training and a control group. METHODS: This study will include 180 older adults: 90 healthy patients and 90 patients with osteoporosis. Participants will be allocated randomly in either of the groups, stratified according to age. Training groups will receive 2 weekly 1-hour training sessions, continuously through 6 months. Participants will be tested at baseline and 6 and 18 months post baseline. Primary outcome will be number of falls and secondary outcomes include bone mineral density, body composition, pain evaluation, weekly physical activity, single-task and dual-task gait patterns, balance, Fullerton Functional Fitness Test and assessment of the mini-BESTest. DISCUSSION: This study will investigate the effects of a specially designed dance training programme (Dancing Against falls iN Community-dwElling older adults (DANCE)) to reduce the risk of falling among older adults. The study will investigate the effect against an active and passive comparator, resulting in the possibility to state, if DANCE training should be an alternative to traditional training. TRIAL REGISTRATION NUMBER: NCT03683849.

The effects of pain and a secondary task on postural sway during standing.

BACKGROUND: Pain impairs available cognitive resources and somatosensory information, but its effects on postural control during standing are inconclusive. The aim of this study was to investigate whether postural sway is affected by the presence of pain and a secondary task during standing. METHODS: Sixteen healthy subjects stood as quiet as possible at a tandem stance for 30s on a force platform at different conditions regarding the presence of pain and a secondary task. Subjects received painful stimulations on the right upper arm or lower leg according to a relative pain threshold [pain 7 out 10 on a Visual Analog Scale (VAS) - 0 representing "no pain" and 10 "worst pain imaginable"] using a computer pressurized cuff. The secondary task consisted of pointing to a target using a head-mounted laser-pointer as visual feedback. Center of Pressure (COP) sway area, velocity, mean frequency and sample entropy were calculated from force platform measures. FINDINGS: Compared to no painful condition, pain intensity (leg: VAS = 7; arm VAS = 7.4) increased following cuff pressure conditions (P < .01). Pain at the leg decreased COP area (P < .05), increased COP velocity (P < .05), mean frequency (P < .05) and sample entropy (P < .05) compared with baseline condition regardless the completion of the secondary task. During condition with pain at the leg, completion of the secondary task reduced COP velocity (P < .001) compared with condition without secondary task. INTERPRETATION: Pain in the arm did not affect postural sway. Rather, postural adaptations seem dependent on the location of pain as pain in the lower leg affected postural sway. The completion of a secondary task affected postural sway measurements and reduced the effect of leg pain on postural sway. Future treatment interventions could benefit from dual-task paradigm during balance training aiming to improve postural control in patients suffering from chronic pain.

The tolerance to stretch is linked with endogenous modulation of pain.

OBJECTIVES: The effect of stretching on joint range of motion is well documented, and although sensory perception has significance for changes in the tolerance to stretch following stretching the underlining mechanisms responsible for these changes is insufficiently understood. The aim of this study was to examine the influence of endogenous pain inhibitory mechanisms on stretch tolerance and to investigate the relationship between range of motion and changes in pain sensitivity. METHODS: Nineteen healthy males participated in this randomized, repeated-measures crossover study, conducted on 2 separate days. Knee extension range of motion, passive resistive torque, and pressure pain thresholds were recorded before, after, and 10 min after each of four experimental conditions; (i) Exercise-induced hypoalgesia, (ii) two bouts of static stretching, (iii) resting, and (iv) a remote, painful stimulus induced by the cold pressor test. RESULTS: Exercise-induced hypoalgesia and cold pressor test caused an increase in range of motion (p<0.034) and pressure pain thresholds (p<0.027). Moderate correlations in pressure pain thresholds were found between exercise-induced hypoalgesia and static stretch (Rho>0.507, p=0.01) and exercise-induced hypoalgesia and the cold pressor test (Rho=0.562, p=0.01). A weak correlation in pressure pain thresholds and changes in range of motion were found following the cold pressor test (Rho=0.460, p=0.047). However, a potential carryover hypoalgesic effect may have affected the results of the static stretch. CONCLUSIONS: These results suggest that stretch tolerance may be linked with endogenous modulation of pain. Present results suggest, that stretch tolerance may merely be a marker for pain sensitivity which may have clinical significance given that stretching is often prescribed in the rehabilitation of different musculoskeletal pain conditions where reduced endogenous pain inhibition is frequently seen.

Strength development according with age and position: a 10-year study of 570 soccer players.

BACKGROUND/AIM: The purpose of this study was to compare the isokinetic peak torque profiles from the quadriceps and hamstrings muscles during concentric and eccentric contractions in elite Brazilian soccer players across different field positions and age categories. Our hypothesis was that soccer players from different field positions are subjected to different ageing-related effects on their isokinetic peak torque. METHODS: This is a retrospective study based on professional elite-level soccer players between the years 2009 and 2019. It included 570 adult males who played for at least 5 years on first or second Brazilian divisions. Playing positions were divided as: goalkeepers, defenders, sidebacks, midfielders and forwards. Age categories were also divided as: G1 (17-20 years old), G2 (21-24 years old), G3 (25-28 years old), G4 (29-32 years old) and G5 (33 years old or more). RESULTS: The results indicate a moderate effect of age (F(4545)=8.197; p<0.001; η2=0.057) and a small effect of playing position (F(4545)=2.993; p<0.05; η2=0.021) on torque of concentric extensors; mainly from midfielders and goalkeepers with 29 years or more. CONCLUSIONS: Soccer players from different field positions are subjected to different ageing related effects on their muscular performance during their career special attention should be given to these players to avoid reduction in physical performance.

Concentric and eccentric isokinetic hamstring injury risk among 582 professional elite soccer players: a 10-years retrospective cohort study.

BACKGROUND/AIM: Different authors have tried to correlate the peak isokinetic torque values with the incidence of soccer match injuries. However, due to the wide variety of assessment testing protocols, such an inference becomes difficult. This study aimed to verify the capacity of an isokinetic test to establish injury risk reference values for hamstring strain injuries. METHODS: A retrospective cohort study based on isokinetic data and clinical records from the last 10 years was conducted in 582 Brazilian elite-professional soccer players, who were subjected to the same isokinetic test protocol, machine, and tester. A Multivariate Logistic Regression Analysis for Complex Data Sampling was used to generate injury risk statistical indexes. RESULTS: Multivariate regression analysis of both legs provided important data to identify the cut-off values of Concentric Peak Torque (181.82 Newton/*metres), Concentric Work (236.23 watts) and Concentric Power (130.11 joules). CONCLUSIONS: The injury risk indexes indicate that an increase of just one Newton unit in CPT (Concentric Peak Torque) and CJ (Concentric Power) above those cut-off values, can reduce the risk of future injuries by 2% and 2.7%, respectively.

"Study protocol for the ≥65 years NOrthern jutland Cohort of Fall risk Assessment with Objective measurements (the NOCfao study)".

BACKGROUND: Accidental falls are common among community-dwellers, probably due to the level of physical activity and impaired postural stability. Today, fall risk prediction tools' discriminative validity are only moderate. In order to increase the accuracy, multiple variables such as highly validated objective field measurements of physical activity and impaired postural stability should be adressed in order to predict falls. The main aim of this paper is to describe the ≥65 years NOrthern jutland Cohort of Fall risk Assessment with Objective measurements (NOCfao) investigating the association between physical activity and impaired postural stability and the risk of fall episodes among community-dwelling older adults. METHODS: The study consists of a baseline session where the participants are asked to respond to three questionnaires, perform physical tests (i.e., measuring strength in the upper and lower extremities, balance, and walking speed), participate in an assessment of pain sensitivity, and to wear an ankle mounted pedometer for measuring physical activity for 5 days. Subsequently, the fall incidences and the circumstances surrounding the falls during the previous 1 to 2 months will be recorded throughout a one-year follow-up period. DISCUSSION: This study will add to the present-day understanding of the association between physical activity and impaired postural stability and the risk of fall episodes among community-dwelling older adults. These data will provide valid and reliable information on the relationship between these variables and their significance for community-dwelling older adults. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT2995317. Registered December 13th, 2016.

Validation of different stepping counters during treadmill and over ground walking.

BACKGROUND: Commercially available physical activity trackers are very popular in the general population and are increasingly common in clinical and research settings. The marketfor activity trackers are rapidly expanding, requiring them to be validated on an ongoing basis. Different approaches have been used for validating these devices. Studies using treadmills shows good step-counting accuracy although test performed in field tests settings are limited. RESEARCH QUESTION: Does step-counting validity differ between a field test and a treadmill protocol for different types of activity trackers? METHODS: Thirty healthy subjects participated in this study, mean age was 28.2 (± 4.33) years, body mass 78.9 (± 12.9) kg, and height 178.5 (± 9.7) cm. A treadmill protocol with three different walking speeds (2, 3 and 4 km/h) and a 982 m field test was used. During the tests, participants' feet were filmed using a waist-mounted camera. The number of steps were extracted from the video data and used for comparison with four different step counters: a) Polar M200; b) Polar A300; c) Dunlop pedometer; d) Samsung Galaxy S9 smartphone. Validity and agreement determined was determined with the use of Bland-Altman plot and Spearman's correlation. RESULTS: Validity was higher for the field test compared to the 4 km/h treadmill test for all tested devices. The smartphone was the most accurate in terms of error, validity and agreement for both the treadmill and field test. All devices performed poorly for the 2 km/h treadmill test and only the smartphone performed well at 3 km/h. SIGNIFICANCE: The results of this study show that step counting validity and error obtained during treadmill walking is not similar to a field test. Future validation studies of activity trackers should consider this when designing a protocol. The smartphone had the lowest mean bias during the field test.