The validity and reliability of commercially available smartphone-based velocity-based training applications: A systematic review with guidance for research and practice

PurposeTo compare auto-regulated velocity-based training (VBT) with traditional fixed percentage-based training (PBT) on neuromuscular performance in collegiate sprinters.MethodsTwenty resistance-trained males performed 6 weeks of back squat exercise 3 times per week. Both groups completed five sets of five repetitions with 3-min inter-set rest, matched for exercise selection and volume. The VBT group adjusted load based on real-time barbell velocity to maintain a target mean propulsive velocity of ∼0.54 m·s-1 (≈80% 1RM), whereas the PBT group trained with a fixed 80% of pre-intervention 1RM without further adjustment. Countermovement jump (CMJ), Standing long jump (SLJ), 20-m sprint times (T20-m), maximal strength (1RM back squat), and COD (T-test) were measured pre- and post-intervention.ResultsBoth groups significantly improved CMJ height (VBT: +7.8%, ES = 0.48; PBT: +6.7%, ES = 0.44), relative peak power output (VBT: +4.1%, ES = 0.85; PBT: +3.8%, ES = 0.35), SLJ performance (VBT: +1.0%, ES = 0.37; PBT: +1.8%, ES = 0.15), T20-m sprint times (VBT: −3.7%, ES = 1.30; PBT: −1.6%, ES = 0.51), maximal strength (VBT: +16.4%, ES = 1.57; PBT: +11.5%, ES = 0.94), and COD performance (VBT: −3.2%, ES = 0.54; PBT: −1.5%, ES = 0.39). VBT elicited significantly greater improvements than PBT in 1RM strength, T20-m, and COD performance (P < 0.05), whereas changes in CMJ and SLJ did not differ between groups (P > 0.05).ConclusionBoth training methods improved CMJ, SLJ, T20-m, 1RM back squat, and COD performance, but VBT may be slightly favorable for collegiate sprinters focusing on maximal strength, sprint performance, and COD compared to PBT.

This study examined the effects of velocity-based training (VBT) on free-weight barbell back squat technique compared with traditional resistance training (TR). Ten experienced participants completed anthropometric assessments, one-repetition maximum (1RM) testing, and VBT familiarisation, followed by randomised squat sessions using both methods. During VBT, participants received real-time velocity feedback and lifted with maximal concentric intent; during TR, participants used their habitual technique without feedback. Statistical significance was set at p ≤ 0.05. No significant differences were found in peak joint angles or trunk inclination ( p &gt; 0.05), although small to moderate effects were observed (Hedges’ g ). Mean resultant barbell velocity, the vector sum of horizontal and vertical velocity components, was higher during VBT (0.48 ± 0.05 m·s −1 ) than TR (0.43 ± 0.04 m·s −1 ; p &lt; 0.001), with a large effect; however, the vertical velocity component was greater during TR (94.7 ± 2.1%) than VBT (92.3 ± 3.1%; p = 0.016). The 95% confidence ellipse area of center of pressure (CoP) was larger during VBT (106.7 ± 26.9 cm 2 ) than TR (58.4 ± 16.1 cm 2 ; p &lt; 0.001), with a large effect. Coefficients of variation were comparable across all variables. Collectively, these results indicate that VBT did not significantly alter joint or trunk kinematics, and any observed differences were small and unlikely to be practically meaningful. However, whilst resultant velocity was greater during VBT, this was accompanied by larger CoP perturbations, suggesting greater instability. Practitioners should monitor technique and consider athlete experience, training objectives, and injury risk when implementing VBT.

Velocity-based training (VBT) is commonly used for programming and autoregulation of resistance training. Velocity may also be measured during resistance training to estimate one repetition maximum and monitor fatigue. This study quantifies the validity of Metric VBT, a mobile application that uses camera-vision for measuring barbell range of motion (RoM) and mean velocity during resistance exercises. Twenty-four participants completed back squat and bench press repetitions across various loads. Five mobile devices were placed at varying angles (0, ±10, and ±20°) perpendicular to the participant. The validity of Metric VBT was assessed in comparison to Vicon motion analysis using precision and recall, Lin's concordance correlation coefficient, and Bland-Altman plots. Proportional bias was assessed using linear regression. Metric VBT accurately detected over 95% of repetitions. It showed moderate to substantial agreement with the Vicon system for measuring RoM in both exercises. The average Limits of Agreement (LoA) for RoM across all camera positions were -5.45 to 4.94 cm for squats and -5.80 to 3.55 cm for bench presses. Metric VBT exhibited poor to moderate agreement with the Vicon system for measuring mean velocity. The average LoA for mean velocity were 0.03 to 0.25 m/s for squats and -5.80 to 3.55 m/s for bench presses. A proportional bias was observed, with bias increasing as repetition velocity increased. Metric VBT's wide LoA for measuring RoM and mean velocity highlights significant accuracy concerns, exceeding acceptable levels for practical use. However, for users prioritizing repetition counts over precise RoM or mean velocity data, the application can still provide useful information for monitoring workout volume.

Velocity-based training (VBT) is a contemporary prescriptive, programming, and testing tool commonly utilised in strength and conditioning (S&amp;C). Over recent years, there has been an influx of peer-reviewed literature investigating several different applications (e.g. load-velocity profiling, velocity loss, load manipulation, and reliability of technology) of VBT. The procedures implemented in research, however, do not always reflect the practices within applied environments. The aim of this study, therefore, was to investigate the perceptions and applications of VBT within elite S&amp;C to enhance contextual understanding and develop appropriate avenues of practitioner-focused research. Fourteen high-performance S&amp;C coaches participated in semi-structured interviews to discuss their experiences of implementing VBT into their practices. Reflexive thematic analysis was adopted, following an inductive and realist approach. Three central organising themes emerged: Technology, applications, and reflections. Within these central themes, higher order themes consisting of drivers for buying technology; programming, testing, monitoring, and feedback; and benefits, drawbacks, and future uses also emerged. Practitioners reported varied drivers and applications of VBT, often being dictated by simplicity, environmental context, and personal preferences. Coaches perceived VBT to be a beneficial tool yet were cognizant of the drawbacks and challenges in certain settings. VBT is a flexible tool that can support and aid several aspects of S&amp;C planning and delivery, with coaches valuing the impact it can have on training environments, objective prescriptions, tracking player readiness, and programme success.

This chapter provides some guidelines and framework, and dispel some myths about Velocity-Based Training (VBT). VBT is far from magical or mystical. It is a method of training where feedback of the velocity drives intrinsic motivation. The linear position transducer is a direct measurement of barbell velocity by measuring both distance and time. Camera-based systems utilise the distance travelled within their visual scope and divide by the frame rate as the time portion. Accelerometer-based units will utilise acceleration over their estimated bar path to derive velocity numbers. In team sports, the ability to actually implement a technique is paramount for its success. Velocity loss is another method of using VBT that does not matter if the utilisation is through a team or individualised approach. With velocity loss, there is a prescribed load for the day, and sets are terminated when the athlete loses a certain amount of velocity.

Velocity-based training (VBT) is a resistance training method by which training variables are manipulated based on kinematic outcomes, e.g., barbell velocity. The better precision for monitoring and manipulating training variables ascribed to VBT assumes that velocity is measured and communicated correctly. This study assessed the validity of several mobile and one stationary VBT device for measuring mean and peak concentric barbell velocity over a range of velocities and exercises, including low- and high-velocity, ballistic and non-ballistic, and plyometric and non-plyometric movements, and to quantify the isolated effect of device attachment point on measurement validity. GymAware (r = 0.90–1, standard error of the estimate, SEE = 0.01–0.08 m/s) and Quantum (r = 0.88–1, SEE = 0.01–0.18 m/s) were most valid for mean and peak velocity, with Vmaxpro (r = 0.92–0.99, SEE = 0.02–0.13 m/s) close behind. Push (r = 0.69–0.96, SEE = 0.03–0.17 m/s) and Flex (r = 0.60–0.94, SEE = 0.02–0.19 m/s) showed poorer validity (especially for higher-velocity exercises), although typical errors for mean velocity in exercises other than hang power snatch were acceptable. Effects of device placement were detectable, yet likely small enough (SEE < 0.1 m/s) to be negligible in training settings.

Concurrent validation of the resistance intensity scale for exercise for monitoring velocity-based training with elastic bands

Suchomel, TJ, Kissick, CR, Techmanski, BS, Mann, JB, and Comfort, P. Velocity-based training with weightlifting derivatives: Barbell and system velocity comparisons. J Strength Cond Res 39(2): 135-146, 2025-The aim of this study was to examine the differences in barbell and system (i.e., subject + load) velocity during weightlifting derivatives performed across a spectrum of relative loads. 14 resistance-trained men participated in 6 testing sessions, which included 1 repetition maximum hang power clean (HPC) testing and individual jump shrug (JS), hang high pull (HHP), HPC, hang clean pull (HCP), and countermovement shrug (CMS) sessions. The order of the exercise testing sessions was randomized and required the subjects to perform either JS, HHP, HPC, HCP, or CMS repetitions while standing on a force platform with a linear position transducer attached to the barbell. The JS and HHP were performed with 20, 40, 60, 80, and 100% of their 1 repetition maximum HPC, HPC with 20, 40, 60, and 80% 1RM, and the HCP and CMS performed with 20, 40, 60, 80, 100, 120, and 140% 1RM. Mean and peak barbell and system velocities were determined across all exercises and loads using either 2 × 5, 2 × 4, or 2 × 7 repeated measures ANOVA depending on the number of loads performed. Significantly ( p < 0.001) and meaningfully ( g ≥ 1.49) greater mean and peak barbell velocities existed at every exercise and load combination compared with the mean and peak system velocities produced. Barbell and system velocity are distinct characteristics that should not be substituted for one another. Owing to the characteristics of the transition phase, mean barbell and system velocity may not provide strength and conditioning practitioners with meaningful information related to load prescription.

The aim of the study was to investigate whether resistance-trained participants can accurately predict changes in barbell velocity, specifically in the deadlift exercise, without feedback from velocity based training (VBT) devices. Seventeen participants (16 male, 1 female; age = 24.7 ± 3.8) were randomized in a counterbalanced, crossover design two experimental sessions that consisted of three sets of Deadlift at 60-and-80% one-repetition maximum (1RM). The number of repetitions were determined by the participants as they were asked to terminate each set when they felt the barbell velocity had reduced by 20%, relative to repetition one. A binomial mixed effects regression model was used to assess the accuracy of participants ability to stop after reaching at least 20% velocity loss. Participants tended to underestimate their proximity to 20% velocity loss and thus had relatively low probability of correctly stopping after reaching this threshold. There was only a 10.49% probability that people could perceive at least 20% velocity loss greater than chance (i.e., 50% probability). Our data, suggests that most participants cannot accurately perceive changes in velocity without exposure to augmented feedback.

Resistance training (RT) coaches can implement velocity-based training (VBT) to prescribe set volume by terminating sets at a target velocity loss (VL) threshold. However, VBT necessitates velocity-tracking devices that demand time and expertise. In a previous study, we asked RT coaches to detect VL thresholds using solely their observational judgment - the Coach's Eye. We found improved accuracy when participants spontaneously used a "bar strategy" (focusing on the barbell). Here, we investigated whether coaches could be trained to intentionally use this strategy and whether it would be associated with greater accuracy in detecting VL thresholds. Twenty RT coaches completed one experimental session involving a gaze strategy training intervention. Participants watched an instructional video on the bar strategy, practiced with gaze feedback, and completed a VL detection task. The task involved watching videos of trainees performing bench presses and back squats and detecting 20% and 40% VL thresholds. We examined the frequency of bar strategy use using a one-sided exact binomial test and the accuracy in VL thresholds detection using a negative binomial mixed-effects model. Participants used the bar strategy in most trials (mean proportion = 78.81, 95% CI [0.75, 1.00]). The average absolute error in detecting VL thresholds was 1.5 (SD = 2.3) repetitions. Error decreased when using the bar strategy (-1.23, 95% CI [-1.99, -0.03]), detecting 40% VL thresholds (-1.60, 95% CI [-1.88, -1.26]) compared to 20%, and observing sets loaded with 85% 1RM (-1.59, 95% CI [-1.93, -1.16]) but not with 65% 1RM (-0.48, 95% CI [-1.01, 0.18]) compared to 45% 1RM. Lastly, mental fatigue did not significantly affect accuracy (-0.01, 95% CI [-0.03, 0.01]). This study provides novel evidence that, under laboratory conditions, RT coaches can be trained to use a gaze strategy associated with improved accuracy in detecting barbell VL. Thus, the Coach's Eye may offer a practical, coach-led complement to velocity-tracking devices in VBT, with further studies in real-world settings required to establish its ecological validity.

Background: Only a limited number of studies have examined the effects of short-term, strength–speed-oriented velocity-based training (VBT) on lower-body power in female junior volleyball players and elite female artistic gymnasts. The present study aimed to investigate the impact of a four-week VBT intervention on jump performance and force–velocity characteristics in these athletes. Methods: Seven junior female volleyball players (age: 17.4 ± 0.9 years; height: 179.4 ± 6.5 cm; weight: 74.01 ± 3.5 kg) (top-league team members), and seven elite female artistic gymnasts (age: 17.6 ± 2.9 years; height: 159.6 ± 7.2 cm; weight: 59.3 ± 6.3 kg) (National Team members) completed two weekly training sessions for four weeks, each consisting of four sets of six repetitions of parallel back squats (PBSs) and hip thrusts (HTs). Training loads were regulated using barbell velocity targets (PBSs: 0.46–0.72 m/s; HTs: 0.36–0.60 m/s). Pre- and post-intervention assessments included loaded (15–60% body mass) and unloaded squat jumps (SJs) and countermovement jumps (CMJs) to determine peak power output, jump height, and force–velocity profiles. Results: Volleyball players showed significant improvements in peak power predominantly during loaded SJs (SJ45%: +5.5%, p < 0.01; SJ60%: +5.7%, p < 0.05), whereas gymnasts exhibited greater gains in loaded CMJs (CMJ60%: +7.7%, p < 0.01). In contrast, unloaded SJ and CMJ performances remained largely unchanged for all athletes. Both groups demonstrated a significantly steeper post-intervention force–velocity profile (p < 0.001), indicating an enhanced capacity to produce force at lower movement velocities under external loading. Conclusions: Strength–speed-oriented VBT was effective in improving power production under loaded conditions but had limited transfer to unloaded jump performance. These findings highlight the necessity of subsequent training blocks emphasizing high-velocity, sport-specific movements to optimize explosive performance. Future studies should further investigate low-velocity-loss training protocols as a potential means of enhancing unloaded jump outcomes.

Velocity-based training (VBT) has become popular for managing loads during training sessions. Evaluating the validity of these tools is crucial. This study aimed to independently assess the validity and reliability of a smartphone app, My Jump Lab , which provides real-time barbell velocity and power estimations. Fifty sports science students performed two sets of five squats on a Smith machine with a 30-kg load. Barbell velocity measurements were made using a linear position transducer and the app on an iPad mini-6. Concurrent validity was evaluated using Pearson’s correlation coefficient ( r ) and Bland-Altman plots, while reliability was examined through intraclass correlation coefficient (ICC), coefficient of variation and standard error of measurement. Results showed a high correlation between the instruments for mean concentric velocity ( r = 0.860) and mean power ( r = 0.844), with Bland-Altman plots indicating minimal bias. The app demonstrated excellent reliability for both variables (ICC &gt; 0.90), with acceptable coefficients of variation for mean concentric velocity (7.62%) and mean power (8.17%). These findings suggest that My Jump Lab is a valid and reliable tool for measuring real-time barbell velocity and power in lower body exercises.

Background: Velocity-based training (VBT) requires measurement of the velocity at which the barbell is moved in the concentric phase with regard to different resistance exercises, which provides accurate, indirect estimations of 1 RM. However, for assessing punch performance, no study has been carried out to date. The purpose of this study was to analyse the reliability of the GymAware linear transducer for the measurement of barbell velocity during the landmine push throw (LPT) test using four loads. Methods: Twenty-five healthy, physically active male students, aged 24.13 ± 2.82 years, volunteered to take part in this study. The reliability of the LPT test was measured at two separate visits, with a 2-day interval between them. One series of the test protocol included four parts of the LPT test with progressively increasing loads (20, 25, 30, and 35 kg) and 5 min intervals for rests between loads. Results: For all four loads, excellent intra-rater and test–retest reliability was noted for the mean force variable (ICC = 0.97–0.99). Additionally, very strong and significant correlations were established between measurements (r = 0.96–0.99). Poor reliability was observed for barbell height and total work (ICC below 0.5). A trend of decreasing reliability was detected with increasing barbell load. Furthermore, measurements without the barbell throw were more reliable than those with it. Conclusions: These results support the use of the GymAware linear transducer to track barbell velocity during the LPT test. This device may have valuable practical applications for strength and conditioning coaches. Therefore, we suggest that the LPT assessed with the GymAware linear transducer may be a useful method for evaluating upper limb strength and power during boxing punches.

The use of inertial measurement unit (IMU) has become popular in sports assessment. In the case of velocity-based training (VBT), there is a need to measure barbell velocity in each repetition. The use of IMUs may make the monitoring process easier; however, its validity and reliability should be established. Thus, this systematic review aimed to (1) identify and summarize studies that have examined the validity of wearable wireless IMUs for measuring barbell velocity and (2) identify and summarize studies that have examined the reliability of IMUs for measuring barbell velocity. A systematic review of Cochrane Library, EBSCO, PubMed, Scielo, Scopus, SPORTDiscus, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the 161 studies initially identified, 22 were fully reviewed, and their outcome measures were extracted and analyzed. Among the eight different IMU models, seven can be considered valid and reliable for measuring barbell velocity. The great majority of IMUs used for measuring barbell velocity in linear trajectories are valid and reliable, and thus can be used by coaches for external load monitoring.

The aim of this study was to evaluate the level of agreement in measuring back squat kinematics between an inertial measurement unit (IMU) and a 3D motion capture system (3DMOCAP). Kinematic variables included concentric peak velocity (CPV), concentric mean velocity (CMV), eccentric peak velocity (EPV), eccentric mean velocity (EMV), mean propulsive velocity (MPV), and POP-100: a proprietary variable. Sixteen resistance-trained males performed an incrementally loaded one repetition maximum (1RM) squat protocol. A series of Pearson correlations, 2 × 4 RM ANOVA, Cohen’s d effect size differences, coefficient of variation (CV), and standard error of the estimate (SEE) were calculated. A large relationship existed for all variables between devices (r = 0.78–0.95). Between-device agreement for CPV worsened beyond 60% 1RM. The remaining variables were in agreement between devices with trivial effect size differences and similar CV magnitudes. These results support the use of the IMU, regardless of relative intensity, when measuring EMV, EPV, MPV, and POP-100. However, practitioners should carefully select kinematic variables of interest when using the present IMU device for velocity-based training (VBT), as certain measurements (e.g., CMV, CPV) do not possess practically acceptable reliability or accuracy. Finally, the IMU device exhibited considerable practical data collection concerns, as one participant was completely excluded and 13% of the remaining attempts displayed obvious internal error.