How One Feels During Resistance Exercises: A Repetition-by-Repetition Analysis Across Exercises and Loads

Context: The Feeling Scale (FS) is a unique and underexplored scale in sport sciences that measures affective valence. The FS has the potential to be used in athletic environments as a monitoring and prescription tool. Purpose: To examine whether FS ratings, as measured on a repetition-by-repetition basis, can predict proximity to task failure and bar velocity across different exercises and loads. Methods: On the first day, 20 trained participants (10 females) completed 1-repetition-maximum (1-RM) tests in the barbell bench and squat exercises and were introduced to the FS. In the following 3 sessions, participants completed 3 sets to task failure with either (1) 70% 1-RM bench press, (2) 70% 1-RM squat (squat-70%), or (3) 80% 1-RM squat (squat-80%). Sessions were completed in a randomized, counterbalanced order. After every completed repetition, participants verbally reported their FS ratings. Bar velocity was measured via a linear position transducer. Results: FS ratings predicted failure proximity and bar velocity in all 3 conditions (P < .001, R2 .66–.85). Based on the analysis, which included over 2400 repetitions, a reduction of 1 unit in the FS corresponded to approaching task failure by 14%, 11%, and 11%, and to a reduction in bar velocity of 10%, 4%, and 3%, in the bench, squat-70%, and squat-80%, respectively. Conclusion: This is the first study to investigate whether the FS can be used in resistance-training environments among resistance-trained participants on a repetition-by-repetition basis. The results indicate that the FS can be used to monitor and prescribe resistance training and that its benefits should be further explored.

Sit-to-Stand Power Across the Lifespan: A Cross-Sectional Analysis

Lower-body power measured by a linear position transducer during the sit-to-stand (STS) movement declines with age and may be a predictor of physical disability in older adults. The purpose of this study was to establish normative data for STS power across the lifespan and to determine if differences exist between age cohorts, sexes, and age cohort–sex subgroups. Adults (N = 557) aged 18–89 were divided into five age cohorts and performed the STS connected to a linear position transducer, which calculated power and velocity during the movement. Significantly lower (p < .01) velocity was observed in a younger age cohort in females than males, whereas males saw a significant average power decrement (p < .01) in a younger age cohort than females. STS power norms give clinicians a metric predicting physical disability and may be of particular interest to males as their power production begins to decline at an earlier age.

Reliability and Validity of Three Clinical Methods to Measure Lower Extremity Muscle Power

Background: Lower extremity muscle power is critical for daily activities and athletic performance in clinical populations. Objective: The purpose of this study was to determine the reliability and validity of 3 clinically feasible methods to measure lower extremity muscle power during a leg press. Methods: Ten of 26 subjects performed 2 sessions of 5 submaximal leg presses separated by 3-7 days in this repeated-measures cross-sectional design; the remaining performed 1 test session. Power was calculated independently for each method [simple video, linear position transducer, and accelerometer] and compared to the reference force plate. Test-retest reliability was evaluated using intraclass correlation coefficients (ICC). Pearson’s correlation coefficient (r), Bland-Altman plots with 95% limits of agreement (LOA), and mean bias percentages (%) were used to determine relative and absolute validity. Results: Power measures were reliable for all methods (ICC=.97-.99). All were highly correlated with the force plate (r=.96-.98). Mean bias was -0.8% (LOA: -16.57% to 14.98%) (video), -13.21% (LOA: -23.81% to -2.61%) (position transducer) compared to the force plate. Proportional bias was observed for accelerometry. Conclusion: All methods were reliable and highly correlated with the force plate. Only the video and position transducer demonstrated absolute validity. The position transducer was the most feasible method because of its simplicity and accuracy in measuring power.

How one feels during resistance exercises: A repetition by repetition analysis across exercises and loads

Purpose: The feeling scale (FS) is a unique and underexplored scale in sport sciences that measures affective valence. FS has the potential to be used in athletic environments as a monitoring and prescription tool. We sought to examine whether FS ratings, as measured on a repetition-by-repetition basis, can predict proximity to task-failure and bar velocity across different exercises and loads. Methods: On the first day, 20 trained subjects (10 females) completed 1RM tests in the barbell bench and squat exercises and were introduced to the FS. On the following three sessions, subjects completed three sets to task-failure with either 1) 70%1RM bench-press, 2) 70%1RM squat (squat-70%), or 3) 80%1RM squat (squat-80%). Sessions were completed in a randomized, counter-balanced order. After every completed repetition, subjects verbally reported their FS ratings. Bar velocity was measured via linear position transducer. Results: FS ratings predicted failure-proximity and bar velocity in all three conditions (p&lt;0.001, R2 range: 0.66-0.85). Specifically, a reduction of one unit in the FS corresponded to approaching task-failure by 14%, 11% and 11%, and to a reduction in bar velocity of 10%, 4% and 3%, in the bench, squat-70% and squat-80%, respectively. Conclusion: This is the first study to investigate if the FS can be used in RT environments among trained subjects, on a repetition-by-repetition basis. The results show strong predictive abilities of the FS, indicating that the scale can be used to monitor and prescribe resistance training, and that its benefits should be further explored.

Validity and Reliability of the GymAware Linear Position Transducer for Squat Jump and Counter-Movement Jump Height

The purpose of this study was to assess the concurrent validity and test-retest reliability of a linear position transducer (LPT) for the squat jump (SJ) and counter-movement jump (CMJ) height. Twenty-eight subjects (25.18 ± 7.1 years) performed three SJs followed by three CMJs using a force plate concurrently with the LPT to test validity. Subjects returned on a separate day, at least 48 h apart, to measure test-retest reliability. A t-test showed a significant difference between the two devices for both SJ (p < 0.001) and CMJ (p < 0.001) while Bland–Altman analysis for validity revealed that the LPT overestimated jump height for both SJ (mean difference (MD) = 8.01 ± 2.93 cm) and CMJ (MD = 8.68 ± 2.99 cm). With regards to reliability of the LPT, mean intraclass correlation (ICC) for both SJ (ICC = 0.84) and CMJ (ICC = 0.95) were high, and Bland–Altman analysis showed mean differences lower than minimal detectable change (MDC) between the days for both SJ (MD = 1.89 ± 4.16 cm vs. MDC = 2.72 cm) and CMJ (MD = 0.47 ± 3.23 cm vs. MDC = 2.11 cm). Additionally, there was a low coefficient of variation (CV) between days for both SJ (CV = 3.25%) and CMJ (CV = 0.74%). Therefore, while the LPT overestimates jump height, it is a reliable tool for tracking changes in jump height to measure performance improvement and monitor fatigue.