Validity and reliability of a smartphone application for knee posture quantification and the effects of external markers on the precision of this measure.

BACKGROUND: Technological resources, such as smartphones can contribute to the quantitative assessment of posture. PURPOSES: Test the validity and reliability of using a postural assessment application to quantify the frontal plane knee posture in orthostatism and to test the influence of the use of external markers on the precision of this measure. DESIGN: Methodological study. METHODS: The knee frontal plane posture of 30 volunteers were analyzed by two independent examiners. The photographs were taken with different external marker arrangements. The photographs were analyzed at two moments using the Kinovea software and PhysioCode Posture (PCP) application. Reliability was analyzed using the intraclass correlation coefficient (ICC) between measures with each instrument conducted at two moments with a 7-day interval. Concurrent validity of PCP with Kinovea measure was analyzed using Pearson's correlation coefficient. Standard error measurement (SEM), minimum detectable change (MDC) and Bland Altman plots were analyzed. RESULTS: PCP demonstrated excellent intra-rater [ICC = 0.92 (95% confidence interval [CI] 0.90-0.93)] and inter-rater [ICC = 0.88 (95%CI 0.85-0.90)] reliability. Concurrent validity analysis showed excellent agreement between PCP and Kinovea software (r = 0.88). The use of markers, independent of positioning, did not influence the measurement properties of measures with both softwares. The SEM was inferior to 1.2°, and the MDC was below 2.85°. No systematic errors were observed in the Bland Altman graphs. CONCLUSIONS: The use of PCP application to measure knee posture was valid and demonstrated excellent intra- and inter-rater reliability levels. The use of external markers did not influence the measurement.

Normative reference values for handgrip strength, shoulder and ankle range of motion and upper-limb and lower limb stability for 137 youth judokas of both sexes.

OBJECTIVES: To provide reference values for handgrip strength, shoulder and ankle range of motion (ROM) and upper-limb and lower limb stability for youth judokas of both sexes and investigate the effects of sex and side dominance. DESIGN: Cross-sectional. METHODS: A total of 137 youth judokas from under-18 (n=60) and under-21 (n=77) categories of both sexes were assessed. Handgrip strength was assessed using a Jamar dynamometer, ankle ROM was measured by lunge test, shoulder ROM was assessed by an inclinometer and upper-limb and lower limb stability were assessed by the Closed Kinetic Chain Upper Extremity Stability Test and by the Modified Star Excursion Balance Test (mSEBT). RESULTS: In both categories, males had greater handgrip strength. In the under-18 category, the dominant side had greater handgrip strength, the non-dominant side of females had smaller shoulder external rotation ROM than the dominant side and also than both sides of males, and females had greater shoulder IR ROM. In the under-21 category, the dominant side of females had greater ankle dorsiflexion ROM than the dominant side of males, the dominant sides and females had greater shoulder ER ROM, and males had better performance in the mSEBT. CONCLUSIONS: This study provided reference values for handgrip strength, shoulder and ankle ROM, upper and lower limb stability for youth judokas, which can be used to guide assessment during preseason. Sex influenced on shoulder ER and IR ROM, handgrip strength and lower limb stability. In addition, side dominance influenced on shoulder ER ROM and on handgrip strength.