Comparison of load-velocity relationships in two bench press variations: weight stack machine vs Smith machine.

Performing the bench-press (BP) exercise in a weight stack machine (WSM) is a common practice. However, no previous studies have analysed the load-velocity relationship in this BP variant. The purpose of this study was 1) to investigate the load-velocity relationship during BP exercise using a WSM; and 2) to compare the load-velocity relationship in this exercise in two conditions: WSM vs. Smith machine (SM). Twenty-six young men performed a BP progressive loading test to determine their one-repetition maximum and load-velocity relationship using a WSM. Additionally, 19 participants performed two progressive loading tests (WSM and SM). A high relationship was found between the relative load (%1RM) and mean propulsive velocity (MPV) (R2 = 0.97; SEE = 0.07 m/s) in the WSM. Moreover, significant differences were observed (p <.05) in the MPV values attained in every %1RM in WSM and SM from 30 to 75% 1RM. The close relationship between the MPV values and the %1RM in BP exercise using a WSM enables coaches to use the MPV to accurately monitor their athletes on a daily basis. The differences observed between WSM and SM in the %1RM and their respective MPVs indicate that different equations must be used for each exercise mode.

Concentric-Only Versus Touch-and-Go Bench Press One-Repetition Maximum in Men and Women.

BACKGROUND: One-repetition maximum (1RM) tests are time-consuming, and they might not always be logistically possible or warranted due to increased risk of injury when performed incorrectly or by novice athletes. Repetitions-to-failure tests are a widespread method of predicting the 1RM, but its accuracy may be compromised by several factors such as the type of exercise, sex, training history, and the number of repetitions completed in the test. HYPOTHESIS: The touch-and-go bench press would provide a higher 1RM than the concentric-only bench press for both genders regardless of whether the 1RM was obtained by the direct or repetitions-to-failure method and the error in the 1RM prediction would be positively correlated with the number of repetitions performed to failure and negatively correlated with the 1RM strength and resistance training experience. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 113 adults (87 men and 26 women) were tested on 2 sessions during the concentric-only and touch-and-go bench press. Each session consisted of an incremental loading test until reaching the 1RM load, followed by a repetitions-to-failure test. RESULTS: The 1RM was higher for the touch-and-go bench press using both the direct (men, 7.80%; women, 7.62%) and repetitions-to-failure method (men, 8.29%; women, 7.49%). A significant, although small, correlation was observed between the error in the estimation of the 1RM and the number of repetitions performed (r = 0.222; P < 0.01), 1RM strength (r = -0.169; P = 0.01), and resistance training experience (r = -0.136; P = 0.05). CONCLUSION: The repetitions-to-failure test is a valid method of predicting the 1RM during the concentric-only and touch-and-go bench press variants. However, the accuracy of the prediction could be compromised with weaker and less experienced individuals and if more than 10 repetitions are completed during the repetitions-to-failure test. CLINICAL RELEVANCE: The repetitions-to-failure test does not require any sophisticated equipment and enables a widespread use in different training environments.

A Novel Approach to 1RM Prediction Using the Load-Velocity Profile: A Comparison of Models.

The study aim was to compare different predictive models in one repetition maximum (1RM) estimation from load-velocity profile (LVP) data. Fourteen strength-trained men underwent initial 1RMs in the free-weight back squat, followed by two LVPs, over three sessions. Profiles were constructed via a combined method (jump squat (0 load, 30-60% 1RM) + back squat (70-100% 1RM)) or back squat only (0 load, 30-100% 1RM) in 10% increments. Quadratic and linear regression modeling was applied to the data to estimate 80% 1RM (kg) using 80% 1RM mean velocity identified in LVP one as the reference point, with load (kg), then extrapolated to predict 1RM. The 1RM prediction was based on LVP two data and analyzed via analysis of variance, effect size (g/ηp2), Pearson correlation coefficients (r), paired t-tests, standard error of the estimate (SEE), and limits of agreement (LOA). p < 0.05. All models reported systematic bias < 10 kg, r > 0.97, and SEE < 5 kg, however, all linear models were significantly different from measured 1RM (p = 0.015 <0.001). Significant differences were observed between quadratic and linear models for combined (p < 0.001; ηp2 = 0.90) and back squat (p = 0.004, ηp2 = 0.35) methods. Significant differences were observed between exercises when applying linear modeling (p < 0.001, ηp2 = 0.67-0.80), but not quadratic (p = 0.632-0.929, ηp2 = 0.001-0.18). Quadratic modeling employing the combined method rendered the greatest predictive validity. Practitioners should therefore utilize this method when looking to predict daily 1RMs as a means of load autoregulation.

Movement Velocity as A Measure of Exercise Intensity in Persons with Multiple Sclerosis: A Validity Study.

OBJECTIVES: This study aims to analyse the validity (agreement between two methods) of the movement propulsive velocity (MPV) as an indicator of relative load in leg press (LP) and bench press (BP) exercises in persons with multiple sclerosis (MS). METHODS: 18 persons with MS (sex = 55% male; age (mean SD) = 44.88 10.62 years; body mass = 67.19 10.63 kg; height = 1.66 0.07 m; Expanded Disability Status Scale (EDSS) = 3.12 1.73) performed an incremental loading test in BP and LP exercises in two separate sessions. Individual determination of the one-repetition maximum (1RM) and full load-velocity profile were obtained for each participant. RESULTS: a significant linear relationship was observed between the %1RM load and the MPV in LP (%1RM = -133.58 × MPV + 117.44; r2 = 0.84; standard error of the estimate (SEE) = 9.38%1RM) and BP (%1RM = -95.66 × MPV + 115.26; r2 = 0.86; SEE = 9.82%1RM). In addition, no significant differences were found between the %1RM achieved directly and the %1RM obtained by the equation calculated from the linear regression (LP, p = 0,996; BP, p = 0,749). CONCLUSIONS: these results indicate that movement velocity can estimate the relative load in bench press and leg press exercises in persons MS.