Limits...
Reliability and concurrent validity of a novel method allowing for in-shoe measurement of navicular drop.

Christensen BH, Andersen KS, Pedersen KS, Bengtsen BS, Simonsen O, Kappel SL, Rathleff MS - J Foot Ankle Res (2014)

Bottom Line: To assess concurrent validity, static navicular drop was measured with the stretch-sensor and compared with static navicular drop measured with a ruler on 27 new participants.There was a significant association between static navicular drop measured with the stretch-sensor compared with a ruler (r = 0.745, p < 0.001).Furthermore, the stretch-sensor shows concurrent validity compared with the static navicular drop test as performed by Brody.

View Article: PubMed Central - HTML - PubMed

Affiliation: Orthopaedic Surgery Research Unit, Aalborg University Hospital, Aalborg, Denmark. michaelrathleff@gmail.com.

ABSTRACT

Background: Increased navicular drop is associated with increased risk of lower extremity overuse injuries and foot orthoses are often prescribed to reduce navicular drop. For laboratory studies, transparent shoes may be used to monitor the effect of orthoses but no clinically feasible methods exist. We have developed a stretch-sensor that allows for in-shoe measurement of navicular drop but the reliability and validity is unknown. The purpose of this study was to investigate: 1) the reliability of the stretch-sensor for measuring navicular drop, and 2) the concurrent validity of the stretch-sensor compared to the static navicular drop test.

Methods: Intra- and inter-rater reliability was tested on 27 participants walking on a treadmill on two separate days. The stretch-sensor was positioned 20 mm posterior to the tip of the medial malleolus and 20 mm posterior to the navicular tuberosity. The participants walked six minutes on the treadmill before navicular drop was measured. Reliability was quantified by the Intraclass Correlation Coefficient (ICC 2.1) and agreement was quantified by Limits of Agreement (LOA). To assess concurrent validity, static navicular drop was measured with the stretch-sensor and compared with static navicular drop measured with a ruler on 27 new participants. Linear regression was used to measure concurrent validity.

Results: The reliability of the stretch-sensor was acceptable for barefoot measurement (intra- and inter-rater ICC: 0.76-0.84) but lower for in-shoe measurement (ICC: 0.65). There was a significant association between static navicular drop measured with the stretch-sensor compared with a ruler (r = 0.745, p < 0.001).

Conclusion: This study suggests that the stretch-sensor has acceptable reliability for dynamic barefoot measurement of navicular drop. Furthermore, the stretch-sensor shows concurrent validity compared with the static navicular drop test as performed by Brody. This new simple method may hold promise for both clinical assessment and research but more work is needed before the method can be recommended.

No MeSH data available.


Related in: MedlinePlus

Schematic of the stretch-sensor.
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Figure 2: Schematic of the stretch-sensor.

Mentions: The stretch-sensor is an elastic, flexible, and thin capacitive sensor (Figures 1 and 2). It consists of a stretchable active area that is 15 × 60 mm and a non-stretchable area at both ends that are each 15 × 10 mm, which serve to attach the stretch-sensor to the skin. A change in the stretch of the active area of the sensor causes a linear change in the electrical capacitance. Therefore changes in elongation can be calculated based on the change in the electrical capacitance of the sensor [15]. The thickness of the stretchable area is 0.40–0.60 mm and the thickness is below 1.5 mm in the non-stretchable area, which allows the stretch-sensor to measure in-shoe ND in conventional shoes. The capacitance of the stretch-sensor is measured 200 times per second (200 Hz). The signals from the stretch-sensor are sent to an input box that records the capacitance data on a SD card or transmits the data directly to the computer through a USB cable. Afterwards, the data were analysed using a custom-written script in Matlab [15]. We previously compared the amount of stretch from a calibration slate with the stretch measured from the stretch-sensor and found that the stretch-sensor was valid when compared to a calibration sled with R2 = 0.999 [15].


Reliability and concurrent validity of a novel method allowing for in-shoe measurement of navicular drop.

Christensen BH, Andersen KS, Pedersen KS, Bengtsen BS, Simonsen O, Kappel SL, Rathleff MS - J Foot Ankle Res (2014)

Schematic of the stretch-sensor.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3924915&req=5

Figure 2: Schematic of the stretch-sensor.
Mentions: The stretch-sensor is an elastic, flexible, and thin capacitive sensor (Figures 1 and 2). It consists of a stretchable active area that is 15 × 60 mm and a non-stretchable area at both ends that are each 15 × 10 mm, which serve to attach the stretch-sensor to the skin. A change in the stretch of the active area of the sensor causes a linear change in the electrical capacitance. Therefore changes in elongation can be calculated based on the change in the electrical capacitance of the sensor [15]. The thickness of the stretchable area is 0.40–0.60 mm and the thickness is below 1.5 mm in the non-stretchable area, which allows the stretch-sensor to measure in-shoe ND in conventional shoes. The capacitance of the stretch-sensor is measured 200 times per second (200 Hz). The signals from the stretch-sensor are sent to an input box that records the capacitance data on a SD card or transmits the data directly to the computer through a USB cable. Afterwards, the data were analysed using a custom-written script in Matlab [15]. We previously compared the amount of stretch from a calibration slate with the stretch measured from the stretch-sensor and found that the stretch-sensor was valid when compared to a calibration sled with R2 = 0.999 [15].

Bottom Line: To assess concurrent validity, static navicular drop was measured with the stretch-sensor and compared with static navicular drop measured with a ruler on 27 new participants.There was a significant association between static navicular drop measured with the stretch-sensor compared with a ruler (r = 0.745, p < 0.001).Furthermore, the stretch-sensor shows concurrent validity compared with the static navicular drop test as performed by Brody.

View Article: PubMed Central - HTML - PubMed

Affiliation: Orthopaedic Surgery Research Unit, Aalborg University Hospital, Aalborg, Denmark. michaelrathleff@gmail.com.

ABSTRACT

Background: Increased navicular drop is associated with increased risk of lower extremity overuse injuries and foot orthoses are often prescribed to reduce navicular drop. For laboratory studies, transparent shoes may be used to monitor the effect of orthoses but no clinically feasible methods exist. We have developed a stretch-sensor that allows for in-shoe measurement of navicular drop but the reliability and validity is unknown. The purpose of this study was to investigate: 1) the reliability of the stretch-sensor for measuring navicular drop, and 2) the concurrent validity of the stretch-sensor compared to the static navicular drop test.

Methods: Intra- and inter-rater reliability was tested on 27 participants walking on a treadmill on two separate days. The stretch-sensor was positioned 20 mm posterior to the tip of the medial malleolus and 20 mm posterior to the navicular tuberosity. The participants walked six minutes on the treadmill before navicular drop was measured. Reliability was quantified by the Intraclass Correlation Coefficient (ICC 2.1) and agreement was quantified by Limits of Agreement (LOA). To assess concurrent validity, static navicular drop was measured with the stretch-sensor and compared with static navicular drop measured with a ruler on 27 new participants. Linear regression was used to measure concurrent validity.

Results: The reliability of the stretch-sensor was acceptable for barefoot measurement (intra- and inter-rater ICC: 0.76-0.84) but lower for in-shoe measurement (ICC: 0.65). There was a significant association between static navicular drop measured with the stretch-sensor compared with a ruler (r = 0.745, p < 0.001).

Conclusion: This study suggests that the stretch-sensor has acceptable reliability for dynamic barefoot measurement of navicular drop. Furthermore, the stretch-sensor shows concurrent validity compared with the static navicular drop test as performed by Brody. This new simple method may hold promise for both clinical assessment and research but more work is needed before the method can be recommended.

No MeSH data available.


Related in: MedlinePlus