Background Pain assessment is a key measure that accompanies treatments in a wide range of clinical settings. A low-cost valid and reliable pressure algometer would allow objective assessment of pressure pain to assist a variety of health professionals. However, the pressure algometer is often expensive, which limits its daily use in both clinical and research settings. Objectives This study aimed to assess the instrumental validity, and the intra- and inter-rater reliability of an inexpensive digital adapted pressure algometer. Methods A single rater applied 60 random compressions on a force platform. The pressure pain thresholds of 20 volunteers were collected twice (3 days apart) by two raters. The main outcome measurements were as follows: the maximal peak force (in kPa) and the pressure pain threshold (adapted pressure algometer vs. force platform). Cronbach’s α test was used to assess internal consistency. The standard error of measurement provided estimates of measurement error, and the measurement bias was estimated with the Bland–Altman method, with lower and upper limits of agreement. Results No differences were observed when comparing the compression results (P = 0.51). The validity and internal intra-rater consistencies ranged from 0.84 to 0.99, and the standard error of measurement from 0.005 to 0.04 kPa. Very strong (r = 0.73–0.74) to near-perfect (r = 0.99) correlations were found, with a low risk of bias for all measurements. The results demonstrated the validity and intra-rater reliability of the digitally adapted pressure algometer. Inter-rater reliability results were moderate (r = 0.55–0.60; Cronbach’s α = 0.71–0.75). Conclusion The adapted pressure algometer provide valid and reliable measurements of pressure pain threshold. The results support more widespread use of the pressure pain threshold method among clinicians.

This study aimed to assess the test–retest reliability of a Wii board–based device to assess the eccentric knee strength. Healthy participants (n = 20, 22.7 [3.4] y, 1.71 [0.09] m, 69 [13] kg) performed 2 assessments—days 1 and 2—of the Nordic hamstring exercise (3 trials per day, 3 min of rest between trials, and 48 h between trials) on a padded board with an attached Wii Balance Board (WBB). A ratchet inelastic strap made the contact between the participant’s distal aspect of both legs and the inverted upper surface of the WBB. The means among 3 trials were used to extract the absolute strength and the left and the right limb strengths. No between-session differences were found (P range = .691–.981). The intraclass correlation coefficient range showed excellent results (.905–.926), as the Cronbach α test (above .94). The correlation was high (r > .91; .820 < r2 < .862). The Bland–Altman analysis returned high levels of agreement. The standard error of measurement ranged from 5.56 to 11.07 N and the minimal detectable change from 15.42 to 30.68 N. The percentage of standard error of measurement values were 2.95%, 3.74%, 2.88%, respectively, for absolute strength, right limb strength, and left limb strength. The adapted system showed an excellent cost–benefit relationship with optimal test–retest reliability. The findings suggest that the adapted system, using the WBB, is a reliable method for measuring the eccentric knee strength.

The objective was to assess the instrumental validity and the test–retest reliability of a low-cost hand-held push dynamometer adapted from a load-cell based hanging scale (tHHD) to collect compressive forces in different ranges of compressive forces. Three independent raters applied 50 pre-established compressions each on the tHHD centered on a force platform in three distinct ranges: ~70 N, ~160 N, ~250 N. Knee isometric strength was also assessed on 19 subjects in two sessions (48 h apart) using the tHHD anchored by an inelastic adjustable strap. Knee extension and flexion were assessed with the participant seated on a chair with the feet resting on the floor, knees, and hips flexed at 90°. The isometric force peaks were recorded and compared. The ICC and the Cronbach’s α showed excellent consistency and agreement for both instrumental validity and test–retest reliability (range: 0.89–0.99), as the correlation and determination coefficients (range: 0.80–0.99). The SEM and the MDC analysis returned adequate low values with a coefficient of variation less than 5%. The Bland–Altman results showed consistency and high levels of agreement. The tHHD is a valid method to assess the knee isometric strength, showing portability, cost-effectiveness, and user-friendly interface to provide an effective form to assess the knee isometric strength.

The objective was to assess the instrumental validity and the test-retest reliability of a low-cost hand-held push dynamometer adapted from a load-cell based hanging scale (tHHD) to collect compressive forces in different ranges of compressive forces. Three independent raters applied 50 pre-established compressions each on the tHHD centered on a force platform in 3 distinct ranges: ~70 N, ~160 N, ~250 N. Knee isometric strength was also assessed on 19 subjects in two sessions (48h apart) using the tHHD anchored by an inelastic adjustable strap. Knee extension and flexion were assessed with the participant seated on a chair with the feet resting on the floor, knees, and hips flexed at 90&deg;. The isometric force peaks were recorded and compared. The ICC and the Cronbach&rsquo;s &alpha; showed excellent consistency and agreement for both instrumental validity and test-retest reliability, as the correlation and determination coefficients. The SEM and the MDC analysis returned adequate low values with a coefficient of variation less than 5%. The Bland-Altman results showed consistency and high levels of agreement. The tHHD is a valid method to assess the knee isometric strength, showing portability, cost-effectiveness, and user-friendly interface to provide an effective form to assess the knee isometric strength.

This study aimed to assess the combination of video-based kinematic variables adjusted by intrinsic covariates to predict the relative eccentric force (RelF) during the Nordic curl. The participants (n = 21) performed Nordic curls (3 trials; 3-min rest) on a device measuring the eccentric force. The peaks were normalized by body weight. Kinovea software was used to track angular and linear velocity and acceleration from recorded videos. Two prediction models with multiple linear regression equations associated kinematic, anthropometric, and age variables to adjust the actual RelF. The equations obtained the predicted RelF. The actual RelF was inversely correlated with height (r = −.52), tangential (r = −.50) and centripetal accelerations (r = −.715), and angular velocity (r = −.70). The best prediction models combined angular velocity with age (F2,18 = 15.1, P = .001, r = .792, r2 = .627) and with height (F2,18 = 14.5, P = .001, r = .785, r2 = .616). No differences were observed between actual and predicted values (P = .993−.994), with good levels of agreement and consistency (intraclass correlation coefficient = .77−.78; Cronbach α = .86−.87). Bland–Altman results showed high levels of agreement and low biases. The standard error of measurement and minimal detectable change ranges were 0.46 to 0.49 N/kg and 1.28 to 1.36 N/kg, respectively. Also, the percentage of standard error of measurement was below 10% (7.92%–8.35%). The coefficient of variation analysis returned a 14.54% and 15.13% for each model, respectively. Kinematic analysis offers portability and low cost to current expensive or technical impaired dynamometry-based techniques to assess the RelF.