Test-Retest Reliability Between Free Weight and Machine-Based Movement Velocities

Abstract

Miller, RM, Freitas, EDS, Heishman, AD, Koziol, KJ, Galletti, BAR, Kaur, J, and Bemben, MG. Test-retest reliability between free weight and machine-based movement velocities. J Strength Cond Res XX(X): 000-000, 2018-Several devices are available to measure muscular power through velocity measurement, including the Tendo FitroDyne. The ability for such devices to produce consistent results is still questioned, and the reproducibility of measurement between free weight and machine exercise has yet to be examined. Therefore, the aim of this investigation was to determine the test-retest reliability for barbell velocity during the bench press (BP) and weight velocity during the 2 leg press (2LP) for loads corresponding to 20-80% of 1 repetition maximum (1RM). Forty recreationally active individuals (22.6 ± 2.5 years; 175.9 ± 10.8 cm; and 76.2 ± 13.2 kg) with a 1RM BP and 2LP of 66.8 ± 32.4 kg and 189.5 ± 49 kg, respectively, volunteered for this study. Subjects completed 1 familiarization visit preceding 3 testing visits, which encompassed 1RM determination and 2 days of velocity testing. Forty-eight hours after 1RM testing, the subjects performed 1 repetition at 20, 30, 40, 50, 60, 70, and 80% of their 1RM for each exercise in randomized order. Subjects returned to the laboratory 1 week later to perform the velocity assessment again in randomized order. Intraclass correlation coefficient (ICC2,1) and relative SEM for the BP and 2LP ranged from 0.56 to 0.98 (3-18.1%) and 0.78 to 0.98 (2.8-7.2%), respectively, and no mean differences were observed between trials. The results suggest high reliability for BP velocity between 30 and 60% 1RM and moderate reliability at 20, 70, and 80% 1RM, while the 2LP displayed high to excellent reliability from 20 to 80% 1RM. Cumulatively, machine-based exercise displayed greater reproducibility; however, additional machine exercises need to be examined to bolster this conclusion.

Velocity Performance Feedback During the Free-Weight Bench Press Testing Procedure: An Effective Strategy to Increase the Reliability and One Repetition Maximum Accuracy Prediction

“…Therefore, it seems that the feasibility of the individualized load-velocity relationship to predict the 1RM is more influenced by the exercise type (e.g., BP vs. deadlift) than by the execution mode (machine-guided vs. free-weight). This assumption could be further supported by Balsalobre-Fernández et al (3) who revealed a stronger (i.e., lower SEE ) load-velocity relationship for the free-weight BP exercise compared with the free-weight back squat and deadlift exercises, as well as by other studies that have revealed an acceptable and comparable reliability of velocity outputs for the same exercises performed with free weights or in a Smith machine (11,22,31). Therefore, in line with previous investigations conducted with the BP exercise performed in a Smith machine (10,25), the results of this study also suggest that the free-weight BP 1RM can be obtained with a high precision from the individualized load-velocity relationship.…”

“…The bench press (BP) is an exercise commonly used to assess upper-body pushing performance (26,30). The velocity achieved when lifting a submaximal load at maximal intended velocity is a performance indicator frequently used during BP testing procedures (2,13), which is justified by the high reliability of movement velocity observed for different variants of the BP exercise (11,22,31). However, it is unknown whether the reliability of movement velocity could be influenced by the provision of velocity performance feedback during the BP testing protocol.…”

Assessment of Back-Squat Performance at Submaximal Loads: Is the Reliability Affected by the Variable, Exercise Technique, or Repetition Criterion?

“…For example, the use of a Smith machine, which restricts the movement of the barbell to the vertical direction, may limit the ecological validity of our findings because athletes typically perform the back-squat exercise with free-weights. However, since it has been shown that machine-based exercises provide more reliable measures of movement velocity than free-weight exercises [ 21 ], we decided to use the Smith machine to eliminate the possible confounding factors that could be present during free-weight exercises (e.g., horizontal movements of the barbell). In addition, although it is less frequent in training, resistance training exercises are often performed in a Smith machine for testing purposes [ 11 , 22 , 23 , 24 ].…”

“…Moreover, the back-squat exercise has been shown to report more consistent velocity measurements using the pause technique compared to the rebound technique [ 19 ]. It should be also noted that machine-based exercises can provide more reliable measures of velocity than free-weight exercises [ 21 ], and, consequently, it is common that the testing procedures of mechanical performance against submaximal loads are performed in a Smith machine to reduce the noise of the test [ 11 , 22 , 23 , 24 ]. Therefore, it seems important to compare the reliability of the different performance variables during the back-squat exercise performed in a more controlled environment (i.e., Smith machine) using both the pause and rebound techniques.…”

The role of incline, speed and work rate on the choice of technique in classical roller skiing

“…The leg press [16,17] was performed in a Keiser leg press (Air300 Leg Press, Keiser Corporation, California, USA) and a standardized ten-repetition test was applied. Based on the participants estimated 1RM, the apparatus estimated ten loads with increasing resistance.…”