Reliability and validity assessment of a linear position transducer

The objectives of the study were to determine the validity and reliability of peak velocity (pv),average velocity (av),peak power (pp) and average power (ap) measurements were made using a linear position transducer. validity was assessed by comparing measurements simultaneously obtained using the tendo weightlifting analyzer system® and t-force dynamic measurement system® (ergotech,murcia,spain) during two resistance exercises,bench press (bp) and full back squat (bs),performed by 71 trained male subjects. for the reliability study,a further 32 men completed both lifts using the tendo weightlifting analyzer system® in two identical testing sessions one week apart (session 1 vs. session 2). intraclass correlation coefficients (iccs) indicating the validity of the tendo weightlifting analyzer system® were high,with values ranging from 0.853 to 0.989. systematic biases and random errors were low to moderate for almost all variables,being higher in the case of pp (bias ±157.56 w; error ±131.84 w). proportional biases were identified for almost all variables. test-retest reliability was strong with iccs ranging from 0.922 to 0.988. reliability results also showed minimal systematic biases and random errors,which were only significant for pp (bias -19.19 w; error ±67.57 w). only pv recorded in the bs showed no significant proportional bias. the tendo weightlifting analyzer system® emerged as a reliable system for measuring movement velocity and estimating power in resistance exercises. the low biases and random errors observed here (mainly av,ap) make this device a useful tool for monitoring resistance training. © 2014,journal of sports science and medicine.