Concurrent validity of novel smartphone-based apps monitoring barbell velocity in powerlifting exercises

The aim of this study was to determine the validity of three smartphone applications measuring barbell movement velocity in resistance training and comparing them to a commercially available linear transducer. Twenty competitive powerlifters (14 male and 6 female) completed a progressive loading protocol in the squat, bench press and deadlift (sumo or conventional) until reaching 90% of the highest load they had achieved in a recent competition. Mean velocity was concurrently recorded with three smartphone applications: Qwik VBT (QW), Metric VBT (MT), MyLift (ML), and one linear transducer: RepOne (RO). 3D motion capturing (Vicon) was used to calculate specific gold standard trajectory references for the different systems. A total of 589 repetitions were recorded with a mean velocity of (mean ± standard deviation [min-max]) 0.44 ± 0.17 [0.11-1.04] m·s-1, of which MT and ML failed to identify 52 and 175 repetitions, respectively. When compared to Vicon, RO and QW consistently delivered valid measurements (standardized mean bias [SMB] = 0 to 0.21, root mean squared error [RMSE] = 0.01 to 0.04m·s-1). MT and ML failed to deliver a level of validity comparable to RO (SMB = -0.28 to 0.14, RMSE = 0.04-0.14m·s-1), except for MT in the bench press (SMB = 0.07, RMSE = 0.04m·s-1). In conclusion, smartphone applications can be as valid as a linear transducer when assessing mean concentric barbell velocity. Out of the smartphone applications included in this investigation, QW delivered the best results.

Is two-point method a valid and reliable method to predict 1RM? A systematic review

This systematic review aimed to evaluate the reliability and validity of the two-point method in predicting 1RM compared to the direct method, as well as analyze the factors influencing its accuracy. A comprehensive search of PubMed, Web of Science, Scopus, and SPORTDiscus databases was conducted. Out of the 88 initially identified studies, 16 were selected for full review, and their outcome measures were analyzed. The findings of this review indicated that the two-point method slightly overestimated 1RM (effect size = 0.203 [95%CI: 0.132, 0.275]; P < 0.001); It showed that test-retest reliability was excellent as long as the test loads were chosen reasonably (Large difference between two test loads). However, the reliability of the two-point method needs to be further verified because only three studies have tested its reliability. Factors such as exercise selection, velocity measurement device, and selection of test loads were found to influence the accuracy of predicting 1RM using the two-point method. Additionally, the choice of velocity variable, 1RM determination method, velocity feedback, and state of fatigue were identified as potential influence factors. These results provide valuable insights for practitioners in resistance training and offer directions for future research on the two-point method.

Load-Velocity Relationship Variables to Assess the Maximal Neuromuscular Capacities During the Back-Squat Exercise

BACKGROUND

The relationship between the external load lifted and movement velocity can be modeled by a simple linear regression, and the variables derived from the load-velocity (L-V) relationship were recently used to estimate the maximal neuromuscular capacities during 2 variants of the back-squat exercise.

HYPOTHESIS

The L-V relationship variables will be highly reliable and will be highly associated with the traditional tests commonly used to evaluate the maximal force and power.

STUDY DESIGN

Twenty-four male wrestlers performed 5 testing sessions (a 1-repetition maximum [1RM] session, and 4 experimental sessions [2 with the concentric-only back-squat and 2 with the eccentric-concentric back-squat]). Each experimental session consisted of performing 3 repetitions against 5 loads (45%-55%-65%-75%-85% of the 1RM), followed by single 1RM attempts.

LEVEL OF EVIDENCE

Level 3.

METHODS

Individual L-V relationships were modeled from the mean velocity collected under all loading conditions from which the following 3 variables were calculated: load-axis intercept (L₀), velocity-axis intercept (v₀), and area under the line (A_line = L₀·v₀/2). The back-squat 1RM strength and the maximum power determined as the apex of the power-velocity relationship (P_max) were also determined as traditional measures of maximal force and power capacities, respectively.

RESULTS

The between-session reliability was high for the A_line (coefficient of variation [CV] range = 2.58%-4.37%; intraclass correlation coefficient [ICC] range = 0.98-0.99) and generally acceptable for L₀ and v₀ (CV range = 5.08%-9.01%; ICC range = 0.45-0.96). Regarding the concurrent validity, the correlations were very large between L₀ and the 1RM strength (r_range = 0.87-0.88) and nearly perfect between A_line and P_max (r = 0.98-0.99).

CONCLUSION

The load-velocity relationship variables can be obtained with a high reliability (L₀, v₀, and A_line) and validity (L₀ and A_line) during the back-squat exercise.

CLINICAL RELEVANCE

The load-velocity relationship modeling represents a quick and simple procedure to estimate the maximal neuromuscular capacities of lower-body muscles.

Footwear Affects Conventional and Sumo Deadlift Performance

Barefoot weightlifting has become a popular training modality in recent years due to anecdotal suggestions of improved performance. However, research to support these anecdotal claims is limited. Therefore, the purpose of this study was to assess the differences between the conventional deadlift (CD) and the sumo deadlift (SD) in barefoot and shod conditions. On day one, one-repetition maximums (1 RM) were assessed for thirty subjects in both the CD and SD styles. At least 72 h later, subjects returned to perform five repetitions in four different conditions (barefoot and shod for both CD and SD) at 70% 1 RM. A 2 × 2 (footwear × lifting style) MANOVA was used to assess differences between peak vertical ground reaction force (VGRF), total mechanical work (WORK), barbell vertical displacement (DISP), peak vertical velocity (PV) and lift time (TIME) during the concentric phase. The CD displayed significant increases in VGRF, DISP, WORK, and TIME over the SD. The shod condition displayed increased WORK, DISP, and TIME compared to the barefoot condition. This study suggests that lifting barefoot does not improve performance as no differences in VGRF or PV were evident. The presence of a shoe does appear to increase the DISP and WORK required to complete the lift, suggesting an increased work load is present while wearing shoes.

Rating of Perceived Exertion and Velocity Relationships Among Trained Males and Females in the Front Squat and Hexagonal Bar Deadlift

ABSTRACT

Odgers, JB, Zourdos, MC, Helms, ER, Candow, DG, Dahlstrom, B, Bruno, P, and Sousa, CA. Rating of perceived exertion and velocity relationships among trained males and females in the front squat and hexagonal bar deadlift. J Strength Cond Res 35(2S): S23-S30, 2021-This study examined the accuracy of intraset rating of perceived exertion (RPE) to predict repetitions in reserve (RIR) during sets to failure at 80% of 1 repetition maximum (1RM) on the front squat and high-handle hexagonal bar deadlift (HHBD). Furthermore, the relationship between RPE and average concentric velocity (ACV) during the sets to failure was also determined. Fourteen males (29 ± 6 years, front squat relative 1RM: 1.78 ± 0.2 kg·kg-1, and HHBD relative 1RM: 3.0 ± 0.1 kg·kg-1) and 13 females (30 ± 5 years, front squat relative 1RM: 1.60 ± 0.2 kg·kg-1, and HHBD relative 1RM: 2.5 ± 0.3 kg·kg-1) visited the laboratory 3 times. The first visit tested 1RM on both exercises. During visits 2 and 3, which were performed in a counterbalanced order, subjects performed 4 sets to failure at 80% of 1RM for both exercises. During each set, subjects verbally indicated when they believed they were at "6" and "9" on the RIR-based RPE scale, and ACV was assessed during every repetition. The difference between the actual and predicted repetitions performed was recorded as the RPE difference (RPEDIFF). The RPEDIFF was significantly (p < 0.001) lower at the called 9 RPE versus the called 6 RPE in the front squat for males (9 RPE: 0.09 ± 0.19 versus 6 RPE: 0.71 ± 0.70) and females (9 RPE: 0.19 ± 0.36 versus 6 RPE: 0.86 ± 0.88) and in the HHBD for males (9 RPE: 0.25 ± 0.46 versus 6 RPE: 1.00 ± 1.12) and females (9 RPE: 0.21 ± 0.44 versus 6 RPE: 1.19 ± 1.16). Significant inverse relationships existed between RPE and ACV during both exercises (r = -0.98 to -1.00). These results indicate that well-trained males and females can gauge intraset RPE accurately during moderate repetition sets on the front squat and HHBD.

The influence of compressive gear on maximal load lifted in competitive powerlifting

The competition in powerlifting has been divided into two divisions, with gear equipment (EQ) and without gear equipment (RAW). When competing in the EQ division, additional supportive gear can be worn by the athletes, while in the RAW division such gear is not allowed. The aim of the study was to compare the results of the RAW and EQ powerlifting divisions based on the results of world championships and current world records. One-hundred and twenty powerlifters (63 men, 57 women) were included to the analysis. Post hoc analysis for the results of men’s world championships indicated significantly higher results of the barbell squat (SQ; p < 0.001; ES = 1.31), bench press (BP; p < 0.001; ES = 1.27) and deadlift (DL; p < 0.001; ES = 0.37) for EQ compared to the RAW division. Post hoc analysis for the results of women’s world championships indicated significantly higher results of the SQ (p < 0.001; ES = 1.31), BP (p < 0.001; ES = 1.13) and DL (p < 0.001; ES = 0.71) for the EQ compared to the RAW division. Post hoc analysis for men’s world record indicated significantly higher results in the SQ (p < 0.001; ES = 1.32) and BP (p < 0.001; ES = 1.24) for the EQ compared to the RAW division. Furthermore, there were no significant differences in the results of world records in the DL (p = 0.901; ES = 0.26) between the EQ and RAW divisions. Post hoc analysis for women’s world records indicated significantly higher results in the SQ (p < 0.001; ES = 1.22) and BP (p < 0.001; ES = 1.99) for the EQ compared to RAW division. The main finding of the study was that supportive gear increases maximal load lifted during powerlifting competition.

Decline in Unintentional Lifting Velocity Is Both Load and Exercise Specific

Beck, M, Varner, W, LeVault, L, Boring, J, and Fahs, CA. Decline in unintentional lifting velocity is both load and exercise specific. J Strength Cond Res 34(10): 2709-2714, 2020-When monitoring the mean concentric velocity (MCV) for velocity-based resistance training, often a threshold in the decline in the MCV is used to regulate the number of repetitions performed. However, it is not clear if the decline in the MCV is affected by the type of exercise or the relative load used. Therefore, the purpose of this study was to compare the decline in the MCV between the overhead press (OHP) and deadlift (DL) during sets to fatigue at different loads. Thirty individuals (23 ± 3 years) with current training experience with both the OHP and DL completed a 1 repetition maximum (1RM) protocol for the OHP and DL. Subjects then returned to the laboratory on 2 separate occasions and completed 1 set of the OHP and DL to volitional fatigue at either 70 or 90% of their 1RM in a randomized order. The open barbell system measured the MCV of all repetitions. The absolute and relative (%) decline in the MCV was calculated for each condition and compared between loads (70 vs. 90% 1RM) and between lifts (OHP vs. DL). An alpha level of 0.05 was used at the criterion for statistical significance. The absolute decline in the MCV was greatest for the 70% OHP condition (0.36 ± 0.12 m·s) followed by 90% OHP (0.19 ± 0.10 m·s), 70% DL (0.16 ± 0.08 m·s), and 90% DL (0.09 ± 0.06 m·s); all were significantly different from one another (p < 0.05) except for 70% DL vs. 90% OHP (p = 0.441). There was a greater relative decline in the MCV for the OHP compared with the DL (50.1 ± 11.8% vs. 28.5 ± 11.8%; p < 0.001) and for 70% 1RM compared with 90% 1RM (44.5 ± 12.0% vs. 34.1 ± 12.0%; p < 0.001). These data suggest the decline in the MCV is both exercise and load specific. Applying a uniform velocity decline threshold for velocity-based training may reduce training volume to different extents depending on the exercise and relative load used.