Show Me, Tell Me, Encourage Me: The Effect of Different Forms of Feedback on Resistance Training Performance

Validity, reliability, and the contributing physical characteristics of a modified 15m prone Yo-Yo Intermittent Recovery Test Level-1 test in elite female rugby league players

This study aims to establish the validity and reliability of the prone Yo-YoIRL1 in elite female rugby league players (part one) and determine the anthropometric and physical characteristics contributing to 15m prone Yo-YoIRL1 performance (part two). Part one, 21 subjects completed one Yo-YoIRL1, one 20m and two 15m prone Yo-YoIRL1 tests over four sessions, with 7-14 days in-between. Part two, ten subjects completed a testing battery, including body mass, height, dual-energy x-ray absorptiometry, isometric mid-thigh pull, isometric bench-press, 10m and 20m sprints and an incremental treadmill test ([Formula: see text]). The 15m prone YoYoIRL1 demonstrated poor reliability with a typical error of 68m (21%) and a smallest worthwhile change of 54m (9%). Validity analysis found the prone versions of the YoYoIRL1 were not sensitive measures of intermittent running performance. Both prone YoYoIRL1 test distances demonstrated large mean bias (76% and -37% respectively) and typical error of the estimate (19% and 21%, respectively) in comparison to the YoYoIRL1. Body mass (r = -0.89), lean mass (r = -0.64), body fat % (r = -0.68), [Formula: see text] (l∙min-1) (r = -0.64), IMTP (r = -0.69), IBP (r = -0.15), 10m (r = -0.77) and 20m (r = -0.72) momentum displayed large negative relationships with 15m prone Yo-YoIRL1 performance. Due to the poor validity of the 20m prone YoYoIRL1, the poor validity and reliability of the 15m prone YoYoIRL1, and the anthropometric and physical characteristics which negatively impact performance, practitioners should reconsider the use of the prone YoYoIRL1 test to monitor high intensity intermittent running performance.

The Impact of Velocity-Based Training on Load-Velocity Relationships in Leg Press and Chest Press for Older Persons

ABSTRACT

Calaway, C, Mishra, S, Parrino, R, Martinez, KJ, Mann, JB, and Signorile, JF. Velocity-based training affects the load-velocity relationship in leg press and chest press for older persons. J Strength Cond Res 38(6): 1136-1143, 2024-This study examined the impact of 3 months of velocity-based training (VBT) on chest press (CP) and leg press (LP) maximal strength (1 repetition maximum [1RM]), peak power (PP), and percentage load where PP was achieved (%1RMPP) in older adults. Twenty-nine subjects were assigned to either a velocity-deficit (VD) group or a force-deficit (FD) group for each exercise depending on their load-velocity (LV) curves. Changes in load were determined by the ability to maintain either 90% (VD) or 70% (FD) of their PP during training. Subjects' powers were tested before and after the training intervention at loads between 40 and 80%1RM. Separate 2 (group) × 2 (time) ANOVA was used to examine changes in each variable by group for each exercise. Wilcoxon signed-rank tests were used to determine whether significant changes in %1RMPP for each exercise and group. For chest press 1 repetition maximum, there were no significant main effects or interaction. Significant main effects for time were observed for leg press 1 repetition maximum ( p < 0 .001, η2 = 0.547) and chest press peak power ( p = 0.009, η2 = 0.243). For LPPP, there were no significant main effects or interactions. For %1RMPP, CP median scores revealed no significant changes for either group. Significant declines in %1RMPP were observed for leg press velocity-deficit and leg press force-deficit ( p < 0.03) groups. Velocity-based training was effective at improving 1RM, PP, and shifting %1RMPP in the LP groups. These results have implications for targeting power improvements at specific areas of the LV curve. Health care providers and trainers should consider these findings when constructing exercise programs to counter age-related declines in older adults.

Effect of Visual Biofeedback Obtained Using the Iowa Oral Performance Instrument on the Suprahyoid Muscle Activation Level During Effortful Swallowing Maneuver

Effortful swallowing (ES) is a maneuver prescribed for patients who experience pharyngeal residues after swallowing owing to weakness of the tongue and pharyngeal constrictor muscles. ES can increase the pharyngeal contraction force by intentionally increasing the degree of effort during swallowing. However, the effect is limited as the nature of swallowing makes it difficult to maintain a constant high-effort level. The aim of this study was to assess the effect of visual feedback, delivered by the Iowa Oral Performance Instrument (IOPI), a tongue pressure measurement device on ES maneuver effort. Overall, 34 healthy adults performed five sets of ten ES, once every 10 s. The ES maneuver was conducted under two conditions, ES with and without IOPI biofeedback in a crossover design. IOPI biofeedback was provided at 80% of the maximum posterior oral tongue pressure. The suprahyoid muscle activation level was assessed using surface electromyography during the ES maneuver. The mean suprahyoid muscle activation levels in all sets for which IOPI biofeedback was provided were significantly higher than those during ES maneuver without biofeedback (p < 0.05). IOPI biofeedback can help maintain the ES maneuver target effort, utilizing a constantly high swallowing pressure potentially promoting better pharyngeal pressures and muscle strength.

Resistance Training Intensity Prescription Methods Based on Lifting Velocity Monitoring

Resistance training intensity is commonly quantified as the load lifted relative to an individual's maximal dynamic strength. This approach, known as percent-based training, necessitates evaluating the one-repetition maximum (1RM) for the core exercises incorporated in a resistance training program. However, a major limitation of rigid percent-based training lies in the demanding nature of directly testing the 1RM from technical, physical, and psychological perspectives. A potential solution that has gained popularity in the last two decades to facilitate the implementation of percent-based training involves the estimation of the 1RM by recording the lifting velocity against submaximal loads. This review examines the three main methods for prescribing relative loads (%1RM) based on lifting velocity monitoring: (i) velocity zones, (ii) generalized load-velocity relationships, and (iii) individualized load-velocity relationships. The article concludes by discussing a number of factors that should be considered for simplifying the testing procedures while maintaining the accuracy of individualized L-V relationships to predict the 1RM and establish the resultant individualized %1RM-velocity relationship: (i) exercise selection, (ii) type of velocity variable, (iii) regression model, (iv) number of loads, (v) location of experimental points on the load-velocity relationship, (vi) minimal velocity threshold, (vii) provision of velocity feedback, and (viii) velocity monitoring device.

The Effects and Reproducibility of 10, 20, and 30% Velocity Loss Thresholds on Acute and Short-Term Fatigue and Recovery Responses

ABSTRACT

Weakley, J, Johnston, RD, Cowley, N, Wood, T, Ramirez-Lopez, C, McMahon, E, and García-Ramos, A. The effects and reproducibility of 10, 20, and 30% velocity loss thresholds on acute and short-term fatigue and recovery responses. J Strength Cond Res 38(3): 465-473, 2024-This study aimed to establish the effects and reproducibility of implementing 10, 20, and 30% velocity loss thresholds (VLTs) during the free-weight barbell back squat on acute and short-term perceived soreness, neuromuscular fatigue, and physical performance. Using a repeated, counterbalanced, crossover design, 12 team-sport athletes completed on separate sessions 5 sets of the free-weight barbell back-squat until reaching VLTs of either 10, 20, or 30%. Outcomes were measured immediately postexercise and 24 hours after each session. To assess reproducibility, the same sessions were repeated after 4 weeks. Immediately postexercise, small differences in countermovement jump (CMJ) and 10-m sprint performance were observed between VLT conditions, whereas small to moderate differences in differential ratings of perceived exertion were reported (10% < 20% < 30%). At 24 hours, trivial differences in CMJ outcomes were found but small differences in 10-m sprint performance were detected between conditions (10% < 20% < 30%). In addition, at 24 hours, a single small difference in radial deformation using tensiomyography was found between 10 and 30% conditions, whereas large to very large differences in perceived soreness were reported between conditions (10% < 20% < 30%). Finally, the standard error of measurement of all outcome measures at 24 hours were of a similar magnitude to those reported in tightly controlled, short-term studies. Collectively, these findings demonstrate that VLTs help control the fatigue outcomes that occur as a response to resistance training and that they are reproducible. Therefore, for practitioners who wish to prescribe resistance training and be confident in the subsequent fatigue response, it is strongly advised that VLTs are implemented.

Verbal Encouragement Provokes Significant Increases in Maximal Volitional Dynamic Postural Sway

Limits of Stability protocols are typically target-oriented, leaving volitional aspects of control unobservable. A novel unconstrained protocol, volitional Limits of Stability (vLOS), shows high test-retest-reliability. We tested if verbal encouragement impacts this protocol. Forty healthy young adults (age 20.1 ± .9 years) performed three trials of vLoS with instructions that were agnostic to strategy or vigor, except trial three included verbal encouragement. Total sway area was used to metric the maximum volitional dynamic sway during each 1-min trial. One-way, repeated-measures ANOVA revealed significant differences (F(2,117) = 41.56, p < 0.0001, η p 2 = 0.52) due to encouragement. Specifically, follow-up paired t-tests showed no difference in sway area between the first two trials (p = 0.61), while trial three was much larger than trials one and two (p < 0.0001). Significant, large increases in sway area with verbal encouragement indicate that top-down mechanisms should be considered in theories of postural control. As well, clinical utilization of novel vLOS should be careful with word selection and delivery of protocol instructions.HIGHLIGHTSLimits of Stability balance tests typically include a goal directed instruction and metrics.Dynamic postural sway should be tested in a task affording participant volitional control.A novel volitional Limits of Stability protocol has been developed.Maximal dynamic postural sway responds to motivating instructions.Psychological factors of postural sway control deserve further investigation.

Effect of individualised strength and plyometric training on the physical performance of basketball players

The aims of this study were to examine the effects of eight weeks of individualised force-velocity imbalance (F-Vimb) training on physical performance in basketball players and to analyse the differences in physical performance between two periods of time (four to eight weeks) with this training. Thirty male players (age, 22.8 ± 5.68 years; height, 1.87 ± 0.07 m; body mass, 86.3 ± 11.1 kg) were divided into an intervention group (INT, n = 15), who performed an individualised training based on individual F-Vimb; and a control group (CON, n = 15), who underwent a non-individualised training programme; both groups performed two days/week of intervention and the same pre-season basketball training. At baseline, at four weeks, and at eight weeks of intervention, an assessment was performed including countermovement-jumps, unilateral drop jumps, triple hop test, force-velocity profile, sprint and change of direction (COD). At four weeks, the INT showed improvements in sprint and vertical jumping actions (≥3.76%, ES ≥0.44, p ≤ 0.02). At eight weeks, the INT continued to improve vertical jumping actions (p < 0.05) and showed improvements in horizontal jumping (6.80%, ES = 0.45, p < 0.01) and COD (≥2.99%, ES ≥0.96, p < 0.01). A significant reduction in F-Vimb was observed for INT (ES = 0.77, p = 0.01). In contrast, none of these changes were observed in CON. Thus, an individualised F-Vimb training intervention improved physical performance after eight weeks, with changes in sprint and vertical jump after first four weeks. Basketball coaches should optimise the force-velocity profile and improve the performance in sport-related actions as jumping and changing direction.

The 2-Point Method: Theoretical Basis, Methodological Considerations, Experimental Support, and Its Application Under Field Conditions

The "2-point method," originally referred to as the "2-load method," was proposed in 2016 by Prof Slobodan Jaric to characterize the maximal mechanical capacities of the muscles to produce force, velocity, and power. Two years later, in 2018, Prof Jaric and I summarized in a review article the scientific evidence showing that the 2-point method, compared with the multiple-point method, is capable of providing the outcomes of the force-velocity (F-V) and load-velocity (L-V) relationships with similar reliability and high concurrent validity. However, a major gap of our review was that, until 2018, the feasibility of the 2-point method had only been explored through testing procedures based on multiple (more than 2) loads. This is problematic because (1) it has misled users into thinking that implementing the 2-point method inevitably requires testing more than 2 conditions and (2) obtaining the data from the same test could have artificially inflated the concurrent validity of the 2-point method. To overcome these limitations, subsequent studies have implemented in separate sessions the 2-point method under field conditions (only 2 different loads applied in the testing protocol) and the standard multiple-point method. These studies consistently demonstrate that while the outcomes of the 2-point method exhibit comparable reliability, they tend to have slightly higher magnitudes compared with the standard multiple-point method. This review article emphasizes the practical aspects that should be considered when applying the 2-point method under field conditions to obtain the main outcomes of the F-V and L-V relationships.

The Effect of Feedback on Resistance Training Performance and Adaptations: A Systematic Review and Meta-analysis

BACKGROUND

Augmented feedback is often used during resistance training to enhance acute physical performance and has shown promise as a method of improving chronic physical adaptation. However, there are inconsistencies in the scientific literature regarding the magnitude of the acute and chronic responses to feedback and the optimal method with which it is provided.

OBJECTIVE

This systematic review and meta-analysis aimed to (1) establish the evidence for the effects of feedback on acute resistance training performance and chronic training adaptations; (2) quantify the effects of feedback on acute kinematic outcomes and changes in physical adaptations; and (3) assess the effects of moderating factors on the influence of feedback during resistance training.

METHODS

Twenty studies were included in this systematic review and meta-analysis. This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Four databases were searched, and studies were included if they were peer-reviewed investigations, written in English, and involved the provision of feedback during or following dynamic resistance exercise. Furthermore, studies must have evaluated either acute training performance or chronic physical adaptations. Risk of bias was assessed using a modified Downs and Black assessment tool. Multilevel meta-analyses were performed to quantify the effects of feedback on acute and chronic training outcomes.

RESULTS

Feedback enhanced acute kinetic and kinematic outputs, muscular endurance, motivation, competitiveness, and perceived effort, while greater improvements in speed, strength, jump performance, and technical competency were reported when feedback was provided chronically. Furthermore, greater frequencies of feedback (e.g., following every repetition) were found to be most beneficial for enhancing acute performance. Results demonstrated that feedback improves acute barbell velocities by approximately 8.4% (g = 0.63, 95% confidence interval [CI] 0.36-0.90). Moderator analysis revealed that both verbal (g = 0.47, 95% CI 0.22-0.71) and visual feedback (g = 1.11, 95% CI 0.61-1.61) were superior to no feedback, but visual feedback was superior to verbal feedback. For chronic outcomes, jump performance might have been positively influenced (g = 0.39, 95% CI - 0.20 to 0.99) and short sprint performance was likely enhanced (g = 0.47, 95% CI 0.10-0.84) to a greater extent when feedback is provided throughout a training cycle.

CONCLUSIONS

Feedback during resistance training can lead to enhanced acute performance within a training session and greater chronic adaptations. Studies included in our analysis demonstrated a positive influence of feedback, with all outcomes showing superior results than when no feedback is provided. For practitioners, it is recommended that high-frequency, visual feedback is consistently provided to individuals when they complete resistance training, and this may be particularly useful during periods of low motivation or when greater competitiveness is beneficial. Alternatively, researchers must be aware of the ergogenic effects of feedback on acute and chronic responses and ensure that feedback is standardised when investigating resistance training.

Sensor-based augmented visual feedback for coordination training in healthy adults: a scoping review

Introduction

Recent advances in sensor technology demonstrate the potential to enhance training regimes with sensor-based augmented visual feedback training systems for complex movement tasks in sports. Sensorimotor learning requires feedback that guides the learning process towards an optimal solution for the task to be learned, while considering relevant aspects of the individual control system-a process that can be summarized as learning or improving coordination. Sensorimotor learning can be fostered significantly by coaches or therapists providing additional external feedback, which can be incorporated very effectively into the sensorimotor learning process when chosen carefully and administered well. Sensor technology can complement existing measures and therefore improve the feedback provided by the coach or therapist. Ultimately, this sensor technology constitutes a means for autonomous training by giving augmented feedback based on physiological, kinetic, or kinematic data, both in real-time and after training. This requires that the key aspects of feedback administration that prevent excessive guidance can also be successfully automated and incorporated into such electronic devices.

Methods

After setting the stage from a computational perspective on motor control and learning, we provided a scoping review of the findings on sensor-based augmented visual feedback in complex sensorimotor tasks occurring in sports-related settings. To increase homogeneity and comparability of the results, we excluded studies focusing on modalities other than visual feedback and employed strict inclusion criteria regarding movement task complexity and health status of participants.

Results

We reviewed 26 studies that investigated visual feedback in training regimes involving healthy adults aged 18-65. We extracted relevant data regarding the chosen feedback and intervention designs, measured outcomes, and summarized recommendations from the literature.

Discussion

Based on these findings and the theoretical background on motor learning, we compiled a set of considerations and recommendations for the development and evaluation of future sensor-based augmented feedback systems in the interim. However, high heterogeneity and high risk of bias prevent a meaningful statistical synthesis for an evidence-based feedback design guidance. Stronger study design and reporting guidelines are necessary for future research in the context of complex skill acquisition.

The Criterion Validity and Between-Day Reliability of the Perch for Measuring Barbell Velocity During Commonly Used Resistance Training Exercises

ABSTRACT

Weakley, J, Munteanu, G, Cowley, N, Johnston, R, Morrison, M, Gardiner, C, Pérez-Castilla, A, and García-Ramos, A. The criterion validity and between-day reliability of the Perch for measuring barbell velocity during commonly used resistance training exercises. J Strength Cond Res 37(4): 787-792, 2023-This study aimed to assess the criterion validity and between-day reliability (accounting for technological and biological variability) of mean and peak concentric velocity from the Perch measurement system. On 2 testing occasions, 16 subjects completed repetitions at 20, 40, 60, 80, 90, and 100% of 1-repetition maximum in the free-weight barbell back squat and bench press. To assess criterion validity, values from the Perch and a 3-dimensional motion capture system (criterion) were compared. Technological variability was assessed by determining whether the differences between the Perch and criterion for each load were comparable for both testing sessions, whereas between-day reliability with both technological and biological variability was calculated from Perch values across days. Generalized estimating equations were used to calculate R2 and root mean square error, whereas Bland-Altman plots assessed magnitude of difference between measures. To support monitoring of athletes over time, standard error of measurement and minimum detectable changes (MDC) were calculated. There was excellent agreement between the Perch and criterion device, with mean velocity in both exercises demonstrating a mean bias ranging from -0.01 to 0.01 m·s -1 . For peak velocity, Perch underestimated velocity compared with the criterion ranging from -0.08 to -0.12 m·s -1 for the back squat and -0.01 to -0.02 m·s -1 for the bench press. Technological variability between-days were all less than the MDC. These findings demonstrate that the Perch provides valid and reliable mean and peak concentric velocity outputs across a range of velocities. Therefore, practitioners can confidently implement this device for the monitoring and prescription of resistance training.

Development and Evaluation of a Full-Waveform Resistance Training Monitoring System Based on a Linear Position Transducer

Recent advances in training monitoring are centered on the statistical indicators of the concentric phase of the movement. However, those studies lack consideration of the integrity of the movement. Moreover, training performance evaluation needs valid data on the movement. Thus, this study presents a full-waveform resistance training monitoring system (FRTMS) as a whole-movement-process monitoring solution to acquire and analyze the full-waveform data of resistance training. The FRTMS includes a portable data acquisition device and a data processing and visualization software platform. The data acquisition device monitors the barbell's movement data. The software platform guides users through the acquisition of training parameters and provides feedback on the training result variables. To validate the FRTMS, we compared the simultaneous measurements of 30-90% 1RM of Smith squat lifts performed by 21 subjects with the FRTMS to similar measurements obtained with a previously validated three-dimensional motion capture system. Results showed that the FRTMS produced practically identical velocity outcomes, with a high Pearson's correlation coefficient, intraclass correlation coefficient, and coefficient of multiple correlations and a low root mean square error. We also studied the applications of the FRTMS in practical training by comparing the training results of a six-week experimental intervention with velocity-based training (VBT) and percentage-based training (PBT). The current findings suggest that the proposed monitoring system can provide reliable data for refining future training monitoring and analysis.

Effect of Traditional, Rest Redistribution, and Velocity-Based Prescription on Repeated Sprint Training Performance and Responses in Semiprofessional Athletes

ABSTRACT

Weakley, J, Castilla, AP, Ramos, AG, Banyard, H, Thurlow, F, Edwards, T, Morrison, M, McMahon, E, and Owen, C. The effect of traditional, rest redistribution, and velocity-based prescription on repeated sprint training performance and responses in semi-professional athletes. J Strength Cond Res XX(X): 000-000, 2022-The aim of this study was to investigate the effects of traditional, rest redistribution, and velocity-based repeated sprint training methods on repeated sprint performance, perceived effort, heart rate, and changes in force-velocity-power (FVP) profiles in male semiprofessional athletes. In a randomized crossover design, a traditional (2 sets of 6 repetitions [TRAD]), 2 different rest redistribution (4 sets of 3 repetitions [RR4] and 12 sets of 1 repetition [RR12]), and a 5% velocity loss (VL5%) (12 repetitions, with sets terminated when a 5% reduction in mean velocity had occurred) condition were completed. Mean and peak velocity, mean heart rate, and differential ratings of perceived exertion (dRPE) were measured throughout each session, while horizontal FVP profiles were assessed presession and postsession. The RR4 and RR12 conditions allowed the greatest maintenance of velocity, while the RR4, RR12, and VL5% had a moderate, significantly greater mean heart rate than the traditional condition. Trivial, nonsignificant differences between all conditions were observed in dRPE of the legs and breathlessness and FVP profiles. These findings indicate that rest redistribution can allow for greater maintenance of sprint velocity and heart rate, without altering perceived effort during repeated sprint training. In addition, velocity-loss thresholds may be a feasible method of prescription if athletes have diverse physical qualities and reductions in sprint performance during repeated sprint training are undesirable. Practitioners should consider these outcomes when designing repeated sprint training sessions because the strategic use of these methods can alter sprint performance and internal load without changing perceptions of intensity.

Effects of Low- Versus High-Velocity-Loss Thresholds With Similar Training Volume on Maximal Strength and Hypertrophy in Highly Trained Individuals

AIMS

In the present intervention study, low-velocity-loss (LVL) versus high-velocity-loss (HVL) thresholds in the squat and bench press were compared for changes in muscle strength, power, and hypertrophy.

METHODS

Strength-trained volunteers (7♀ and 9♂; age: 27.2 [3.4] y; height: 174.6 [8.0] cm; body mass: 75.3 [10.1] kg) were randomized into an LVL or HVL threshold group (LVL n = 3♀ + 5♂, and HVL n = 4♀ + 4♂). Training took place 3 times per week over 6 weeks (loads: ∼75%-90% of 1-repetition maximum [1RM]). The thresholds of LVLs and HVLs were set at 20% and 40% of maximal velocity, respectively, for the squat, and at 30% and 60%, respectively, for the bench press. Before and after the intervention, 1RM, leg press power, and squat jump were tested. The load (∼45% of 1RM) corresponding to 1-m/s velocity was assessed in all sessions for both exercises. In addition, the thickness of the vastus lateralis and triceps brachii and body composition (dual-energy X-ray absorptiometry [DEXA]) were measured.

RESULTS

Squat and bench-press 1RM increased similarly in both groups by 7% to 11% (SD: 4%-6%, P < .05). No group differences were observed for changes in jump height, leg press power, or DEXA lean mass. However, HVL showed a small increase in muscle thickness of the vastus lateralis compared with LVL (6 ± 6% [95% CI] group difference, P < .05).

CONCLUSION

For strength-trained individuals, high-volume lower-velocity-loss thresholds were as effective as higher thresholds for improvements in 1RM strength; but local hypertrophy was seemingly elicited faster with higher velocity-loss thresholds.

Optimal Minimum Velocity Threshold to Estimate the 1-Repetition Maximum: The Case of the Smith Machine Bench Press Exercise

PURPOSE

To compare the accuracy in the estimation of the Smith machine bench press 1-repetition maximum (1RM) when using a novel minimum velocity threshold (MVT) called optimal MVT (MVT that minimizes the differences between the actual and predicted 1RM in a preliminary session) with respect to using the 2 standard MVTs (general and individual MVTs).

METHODS

A total of 126 young men (Smith machine bench press 1RM = 80.7 [13.6] kg) completed 2 identical sessions consisting of an incremental loading test until reaching the 1RM load. Four individual load-velocity relationships were modeled in each session considering all loading conditions until reaching the load that showed the closest mean velocity to 0.60, 0.50, 0.40, and 0.30 m·s-1. The first testing session was used to determine the preindividual MVT and 4 optimal MVTs (1 for each final test velocity), while the second testing session was used to estimate the 1RM using 4 types of MVT (general MVT, preindividual MVT, actual-individual MVT, and optimal MVT).

RESULTS

The absolute errors in the prediction of the 1RM were significantly lower for the optimal MVT (2.94 [2.40] kg) compared to the general MVT (3.66 [2.99] kg), preindividual MVT (3.80 [3.15] kg), and actual-individual MVT (4.02 [3.21] kg). The optimal MVT (intraclass correlation coefficient [ICC] ranged from .56 to .62) was always more reliable than the individual MVT (ICC = .34).

CONCLUSIONS

The optimal MVT provides more accurate estimates of the Smith machine bench press 1RM than the standard MVTs previously used in scientific research (general and individual MVTs).

The impact of augmented feedback (and technology) on learning and teaching cricket skill: A systematic review with meta-analysis

Augmented feedback, including that provided using technology, can elicit multifaceted benefits on perceptual-motor learning and performance of sporting skills. However, current considerations of the applied value in supporting learning and teaching cricket skill is limited. This systematic review with meta-analysis aimed to understand the role and effectiveness of feedback-involved interventions on skill-based performance outcomes in cricket-related research. Six electronic databases were searched (SPORTDiscus, CINAHL, MEDLINE, Scopus, Web of Science and PsycINFO). Of 8,262 records identified, 11 studies met inclusion criteria; five of which were included in meta-analyses. Given no studies with an isolated feedback intervention-arm were identified, the two meta-analyses explored anticipation-based studies consisting of an intervention that included augmented feedback; positioned with respect to the key motor skill concepts of perception (anticipation accuracy) and action (performance success). Despite results highlighting improved performance outcomes for the feedback-involved intervention groups, with a large effect size for improved anticipation accuracy (Hedge's g = 1.21, 95% CIs [-0.37, 2.78]) and a medium effect size for overall performance success (Hedge's g = 0.55, 95% CIs [-0.39, 1.50]), results were not statistically significant and should be interpreted with caution given the wide confidence intervals. Considering the small number of studies available, in addition to the lack of isolated feedback protocols, further research is warranted to thoroughly explore the impact of augmented feedback on skill-based performance in cricket. Beyond the meta-analyses, the review also explored all included studies from an ecological dynamics perspective; presenting future avenues of research framed around evaluating the applied value of using augmented feedback (mediated with or without technology) for learning and teaching skill in cricket. Trial registration The protocol was preregistered with Open Science Framework (osf.io/384pd).

Reliability of the Wii Balance Board for measurement of steady state balance in children aged 6-9 years

PURPOSE

The Wii Balance Board (WBB) can be used for assessment of steady state balance (SSB), but its reliability has not been studied in children aged 6-9 years. This study aimed to determine the test-retest reliability of the WBB for measuring SSB in this population. A secondary aim was to determine the minimum detectable change (MDC) and standard error of measurement (SEM) of the WBB in children aged 6-9 years.

METHODS

52 children between 6-9 years of age participated. "One leg stand balance" was used to assess center of pressure velocity (COPV) and center of pressure area (COPA) on three occasions by the same tester. Two tests were conducted on the same day (Day 1) and the third test was performed on another day (Day 2), with a period of 5-13 days between the two test days. Intraclass correlation coefficient (ICC 3,1), SEMs, and MDC were calculated.

RESULTS

Intra-day test-retest reliability of COPA was found to be good (ICC3,1 =0.86; 95% confidence interval [CI]: 0.75, 0.92) and that of COPV was also found to be good (ICC3,1 =0.87; 95% CI: 0.77, 0.92). Inter-day test-retest reliability was found to be good for COPA (ICC3,1 = 0.87; 95% CI: 0.75, 0.93) and COPV (ICC3,1 = 0.89; 95% CI: 0.81, 0.94). SEM for COPA in intra-day testing was 18.90 mm2 (15.78%), and in inter-day testing it was 16.44 mm2 (13.61%). SEM for COPV in intra-day testing was 1.12 mm/s (7.6%), and in inter-day testing it was 1.01 mm/s (6.9%). MDC for COPA in intra-day testing was 52.41mm2 (42.75%), and in inter-day testing was 45.58 mm2 (35.75%). MDC for COPV in intra-day testing was 3.11 mm/s (21.2%), and in inter-day testing it was 2.80 mm/s (18.9%).

CONCLUSION

The WBB has good test-retest reliability for assessing SSB of children between 6-9 years. COPA measurements appear to be less sensitive to clinical changes in SSB when compared to COPV. Assessment of validity of the WBB in this age group is recommended before it can be considered as a potential balance assessment tool in children.

Repetitions in Reserve Is a Reliable Tool for Prescribing Resistance Training Load

ABSTRACT

Lovegrove, S, Hughes, L, Mansfield, S, Read, P, Price, P, and Patterson, SD. Repetitions in reserve is a reliable tool for prescribing resistance training load. J Strength Cond Res 36(10): 2696-2700, 2022-This study investigated the reliability of repetitions in reserve (RIR) as a method for prescribing resistance training load for the deadlift and bench press exercises. Fifteen novice trained men (age: 17.3 ± 0.9 years, height: 176.0 ± 8.8 cm, body mass: 71.3 ± 10.7 kg) were assessed for 1 repetition maximum (1RM) for deadlift (118.1 ± 27.3 kg) and bench press (58.2 ± 18.6 kg). Subsequently, they completed 3 identical sessions (one familiarization session and 2 testing sessions) comprising sets of 3, 5, and 8 repetitions. For each repetition scheme, the load was progressively increased in successive sets until subjects felt they reached 1-RIR at the end of the set. Test-retest reliability of load prescription between the 2 testing sessions was determined using intraclass correlation coefficient (ICC) and coefficient of variation (CV). A 2-way analysis of variance with repeated measures was used for each exercise to assess differences in the load corresponding to 1-RIR within each repetition scheme. All test-retest comparisons demonstrated a high level of reliability (deadlift: ICC = 0.95-0.99, CV = 2.7-5.7% and bench press: ICC = 0.97-0.99, CV = 3.8-6.2%). Although there were no differences between time points, there was a difference for load corresponding to 1-RIR across the 3 repetition schemes (deadlift: 88.2, 84.3, and 79.2% 1RM; bench press: 93.0, 87.3, and 79.6% 1RM for the 3-, 5-, and 8-repetition sets, respectively). These results suggest that RIR is a reliable tool for load prescription in a young novice population. Furthermore, the between-repetition scheme differences highlight that practitioners can effectively manipulate load and volume (repetitions in a set) throughout a training program to target specific resistance training adaptations.

Concurrent and Predictive Validity of an Exercise-Specific Scale for the Perception of Velocity in the Back Squat

BACKGROUND

the aim of the study was to develop and validate a specific perception velocity scale for the Back Squat exercise to discriminate the velocity of each repetition during a set.

METHODS

31 resistance trained participants completed 3 evaluation sessions, consisting of 3 blinded loads (light, medium, heavy). For each repetition, barbell mean velocity (Vr) was measured with a linear position transducer while perceived velocity (Vp) was reported using the Squat Perception of Velocity (PV) Scale.

RESULTS

Pearson correlation coefficients (r) showed very high values for each intensity in the 3 different days (range r = 0.73-0.83) and practically perfect correlation for all loads (range r = 0.97-0.98). The simple linear regression analysis between Vp and Vr revealed values ranging from R² = 0.53 to R² = 0.69 in the 3 intensities and values ranging from R² = 0.95 to R² = 0.97 considering all loads. The reliability (ICC_2.1, SEM) of Vp was tested for light (0.85, 0.03), medium (0.90, 0.03) and heavy loads (0.86, 0.03) and for all loads (0.99, 0.11). The delta score (ds = Vp - Vr) showed higher accuracy of the PV at heavy loads.

CONCLUSIONS

these results show that the PV Squat Scale is a valid and reliable tool that can be used to accurately quantify exercise intensity.

The effects of technological and traditional feedback on back squat performance in untrained women

BACKGROUND

Recently, a novel method for improving movement quality called open-ended augmented feedback has been introduced. However, the effects of using such feedback in a training intervention have not yet been examined. The aim of this study was to assess the changes in performance and movement quality following a five-week resistance-training program with either (1) technological feedback or (2) traditional, verbal feedback from an experienced trainer.

METHODS

Nineteen untrained females (age: 21.84 ± 2.24 years, height: 169.95 ± 5.92 cm, body mass: 65.05 ± 7.93 kg) randomly allocated to one of the two conditions completed five weeks of training with two weekly sessions. Pre- and post-intervention, participants were tested for physical performance (i.e., back squat and isometric mid-thigh pull strength) and movement quality parameters (weight distribution, center of gravity variation, and subjective rating of the back squat technique).

RESULTS

Both groups similarly increased the training resistance throughout the intervention (p < 0.01), as well as strength in the back squat (technological feedback group: effect size (ES) = 1.31, p = 0.002; traditional feedback group: ES = 1.48, p = 0.002). Only the traditional feedback group increased isometric mid-thigh pull strength (ES = 1.11, p = 0.008) and subjectively rated lifting technique at the same load (p = 0.046). No changes in force distribution (p = 0.062-0.993) or center of gravity variation (p = 0.160-0.969) occurred in either group when lifting the same absolute loads at post-test. However, both groups displayed a greater variation in center of gravity when lifting the same relative load at post-test (technological feedback group: p < 0.001; traditional feedback group: p = 0.006). No differences were found between the groups for any of the observed changes (p = 0.205-0.401).

CONCLUSIONS

Five weeks of back-squat training with verbal feedback increased isometric mid-thigh pull strength and subjectively rated lifting technique from pre- to post-test, whereas technological feedback did not. Both methods improved back squat strength and training resistance. For resistance-training beginners, the choice between feedback methods should be based on the desired outcomes and the availability of expertise and equipment.

Effect of Augmented Feedback on Velocity Performance During Strength-Oriented and Power-Oriented Resistance Training Sessions

ABSTRACT

Jiménez-Alonso, A, García-Ramos, A, Cepero, M, Miras-Moreno, S, Rojas, FJ, and Pérez-Castilla, A. Effect of augmented feedback on velocity performance during strength-oriented and power-oriented resistance training sessions. J Strength Cond Res 36(6): 1511-1517, 2022-This study examined the effects of providing instantaneous velocity feedback (knowledge of results [KR]) on velocity maintenance across multiple sets during strength-oriented and power-oriented resistance training (RT) sessions. Seventeen men completed 2 strength-oriented RT sessions (4 sets of 5 repetitions at 75% of 1 repetition maximum [1RM] during the back squat [SQ] and bench press [BP] exercises) in 1 week and 2 power-oriented RT sessions (4 sets of 5 repetitions at 30% of 1RM during the countermovement jump [CMJ] and BP throw [BPT] exercises) in another week. Subjects received verbal velocity performance feedback in 1 session (KR) and no KR was provided in another session. Greater velocities during the 4 sets of both strength-oriented (from 4.6 to 11.6%) and power-oriented (from 1.4 to 3.5%) RT sessions were observed. The increments in velocity performance during the KR condition were greater for the CMJ (2.25 ± 0.14 vs. 2.18 ± 0.17 m·s-1; 3.0%) than the BPT (2.33 ± 0.13 vs. 2.29 ± 0.16 m·s-1; 1.7%) and similarly for the SQ (0.59 ± 0.07 vs. 0.55 ± 0.06 m·s-1; 7.5%) and BP (0.47 ± 0.09 vs. 0.44 ± 0.07 m·s-1; 7.8%). The raw differences in the RT velocity for BPT were positively correlated with the raw differences in the RT velocity for SQ (r = 0.524; p = 0.031) and CMJ (r = 0.662; p = 0.004), but the remaining correlations did not reach a statistical significance (r ≤ 0.370; p ≥ 0.123). Although these results support the provision of velocity performance feedback to increase training quality regardless of the type of RT session, the positive effect of KR seems to be more accentuated during strength-oriented compared with power-oriented RT sessions.

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

ABSTRACT

Jiménez-Alonso, A, García-Ramos, A, Cepero, M, Miras-Moreno, S, Rojas, FJ, and Pérez-Castilla, A. Velocity performance feedback during the free-weight bench press testing procedure: An effective strategy to increase the reliability and one repetition maximum accuracy prediction. J Strength Cond Res 36(4): 1077-1083, 2022-This study aimed to determine whether the verbal provision of velocity performance feedback during the free-weight bench press (BP) exercise influences (a) the within-session reliability and magnitude of mean concentric velocity (MCV) values recorded against a range of submaximal loads and (b) the accuracy of the individualized load-velocity profile to estimate the BP 1 repetition maximum (1RM). Fifteen men (BP 1RM relative to body mass = 1.08 ± 0.22) performed an incremental loading test until reaching the 1RM on 2 separate sessions. Subjects received verbal velocity performance feedback in 1 session (knowledge of results [KR]), and no KR was provided in another session (Control). A linear velocity transducer was used to collect the MCV against 4 loads (40-55-70-85% 1RM), and the BP 1RM was estimated from the individualized load-velocity relationship modeled through the multiple-point (40-55-70-85% 1RM) and 2-point methods (40-85% 1RM). The KR condition provided a higher reliability (coefficient of variation [CV]: KR = 2.41%, Control = 3.54%; CV ratio = 1.47) and magnitude (p = 0.001; effect size [ES] = 0.78) of MCV for the 40% 1RM, but no significant differences in reliability (CV ratio ≤1.15) nor in the magnitude (p ≥ 0.058; ES range = 0.00-0.32) were observed for higher loads. The accuracy in the estimation of the 1RM was higher for the KR (absolute errors: multiple-point = 3.1 ± 2.3 kg; 2-point = 3.5 ± 2.1 kg) compared with the Control condition (absolute errors: 4.1 ± 1.9 kg for both multiple-point and 2-point methods). These results encourage the provision of verbal velocity performance feedback during BP testing procedures.

The placement of linear transducers affects the magnitude but not the intra-session reliability of kinematic variables during the bench press exercise

BACKGROUND: While linear transducers are the most accurate velocity monitoring devices, the horizontal motion of the barbell seems to affect its measurement error. OBJECTIVE: To explore the effect of cable inclination of the GymAware and T-Force linear transducers on the intra-session reliability and magnitude of kinematic variables during the Smith machine bench press exercise. METHODS: Twenty-eight resistance-trained males performed 2 blocks of 12 repetitions (4 repetitions at 40-60-80%1RM). In half of the repetitions with each load the two measuring systems were either vertically aligned with the barbell or positioned 15-cm away from the vertical projection of the barbell. RESULTS: Displacement and mean velocity variables were recorded with a high and comparable intra-session reliability regardless of the cable position and measuring system (CV=𝑟𝑎𝑛𝑔𝑒 1.79–8.38%; ICC=𝑟𝑎𝑛𝑔𝑒 0.69–0.98). The inclined cable position provided a lower displacement and mean velocity than the vertical cable position and the differences were comparable using both the GymAware (⩽ 1.52 cm; ⩽ 0.05 m⋅s-1) and T-Force (⩽ 1.53 cm; ⩽ 0.04 m⋅s-1). CONCLUSIONS: These results indicate that repeatable findings of kinematic variables can be obtained regardless of the cable position, but for comparative purposes, the cable position should remain constant from the start to the end of the lifts.

Improving resistance training prescription through the load-velocity relationship in breast cancer survivors: The case of the leg-press exercise

The aims of this study were: (i) to analyse the load-velocity relationship in the bilateral leg-press exercise in female breast cancer survivors, (ii) to assess whether mean velocity (MV) or peak velocity (PV) show stronger relationship with the relative load, and (iii) to examine whether linear (LA) or polynomic (PA) adjustment predict the velocities associated with each %1RM with greater precision. Twenty-two female breast cancer survivors (age: 50.2 ± 10.8 years, weight: 69.6 ± 15.2 kg, height: 160.51 ± 5.25 cm) completed an incremental load test until 1RM in the bilateral leg-press exercise. The MV and the PV of the concentric phase were measured in each repetition using a linear velocity transducer, and were analysed by regression models using LA and PA. A very close relationship of MV (R²= 0.924; p < 0.0001; SEE = 0.08m^.s^-1 by LA, and R² = 0.952; p < 0.0001; SEE = 0.063 m^.s^-1 by PA) and PV (R² = 0.928; p < 0.0001; SEE = 0.119 m^.s^-1 by LA and R² = 0.941; p < 0.0001; SEE = 0.108 m^.s^-1 by PA) with %1RM were observed. The MV of 1RM was 0.24 ± 0.03 m·s^-1, whereas the PV at 1RM was 0.60 ± 0.10 m^.s^-1. A comprehensive analysis of the bilateral leg-press load-velocity relationship in breast cancer survivors is presented. The results suggest that MV is the most recommendable velocity variable to prescribe the relative load during resistance training, and that the PA presents better accuracy to predict velocities associated with each %1RM, although LA is sufficiently valid to use this model as an alternative to the quadratic model. The implications for resistance training in breast cancer are discussed.

Training for Muscular Strength: Methods for Monitoring and Adjusting Training Intensity

Linear loading, the two-for-two rule, percent of one repetition maximum (1RM), RM zones, rate of perceived exertion (RPE), repetitions in reserve, set-repetition best, autoregulatory progressive resistance exercise (APRE), and velocity-based training (VBT) are all methods of adjusting resistance training intensity. Each method has advantages and disadvantages that strength and conditioning practitioners should be aware of when measuring and monitoring strength characteristics. The linear loading and 2-for-2 methods may be beneficial for novice athletes; however, they may be limited in their capacity to provide athletes with variation and detrimental if used exclusively for long periods of time. The percent of 1RM and RM zone methods may provide athletes with more variation and greater potential for strength-power adaptations; however, they fail to account for daily changes in athlete's performance capabilities. An athlete's daily readiness can be addressed to various extents by both subjective (e.g., RPE, repetitions in reserve, set-repetition best, and APRE) and objective (e.g., VBT) load adjustment methods. Future resistance training monitoring may aim to include a combination of measures that quantify outcome (e.g., velocity, load, time, etc.) with process (e.g., variability, coordination, efficiency, etc.) relevant to the stage of learning or the task being performed. Load adjustment and monitoring methods should be used to supplement and guide the practitioner, quantify what the practitioner 'sees', and provide longitudinal data to assist in reviewing athlete development and providing baselines for the rate of expected development in resistance training when an athlete returns to sport from injury or large training load reductions.

A Comparison of Training With a Velocity Loss Threshold or to Repetition Failure on Upper-Body Strength Development in Professional Australian Footballers

PURPOSE

To compare resistance training using a velocity loss threshold with training to repetition failure on upper-body strength parameters in professional Australian footballers.

METHODS

A total of 26 professional Australian footballers (23.9 [4.2] y, 189.9 [7.8] cm, 88.2 [8.8] kg) tested 1-repetition-maximum strength (FPmax) and mean barbell velocity at 85% of 1-repetition maximum on floor press (FPvel). They were then assigned to 2 training groups: 20% velocity loss threshold training (VL; n = 12, maximum-effort lift velocity) or training to repetition failure (TF; n = 14, self-selected lift velocity). Subjects trained twice per week for 3 weeks before being reassessed on FPmax and FPvel. Training volume (total repetitions) was recorded for all training sessions. No differences were present between groups on any pretraining measure.

RESULTS

The TF group significantly improved FPmax (105.2-110.9 kg, +5.4%), while the VL group did not (107.5-109.2 kg, +1.6%) (P > .05). Both groups significantly increased FPvel (0.38-0.46 m·s-1, +19.1% and 0.37-0.42 m·s-1, +16.7%, respectively) with no between-groups differences evident (P > .05). The TF group performed significantly more training volume (12.2 vs 6.8 repetitions per session, P > .05).

CONCLUSIONS

Training to repetition failure improved FPmax, while training using a velocity loss threshold of 20% did not. Both groups demonstrated similar improvements in FPvel despite the VL group completing 45% less total training volume than the TF group. The reduction in training volume associated with implementing a 20% velocity loss threshold may negatively impact the development of upper-body maximum strength while still enhancing submaximal movement velocity.

Differences between adjusted vs. non-adjusted loads in velocity-based training: consequences for strength training control and programming

Strength and conditioning specialists commonly deal with the quantification and selection the setting of protocols regarding resistance training intensities. Although the one repetition maximum (1RM) method has been widely used to prescribe exercise intensity, the velocity-based training (VBT) method may enable a more optimal tool for better monitoring and planning of resistance training (RT) programs. The aim of this study was to compare the effects of two RT programs only differing in the training load prescription strategy (adjusting or not daily via VBT) with loads from 50 to 80% 1RM on 1RM, countermovement (CMJ) and sprint. Twenty-four male students with previous experience in RT were randomly assigned to two groups: adjusted loads (AL) (n = 13) and non-adjusted loads (NAL) (n = 11) and carried out an 8-week (16 sessions) RT program. The performance assessment pre- and post-training program included estimated 1RM and full load-velocity profile in the squat exercise; countermovement jump (CMJ); and 20-m sprint (T20). Relative intensity (RI) and mean propulsive velocity attained during each training session (V_session) was monitored. Subjects in the NAL group trained at a significantly faster V_session than those in AL (p < 0.001) (0.88-0.91 vs. 0.67-0.68 m/s, with a ∼15% RM gap between groups for the last sessions), and did not achieve the maximum programmed intensity (80% RM). Significant differences were detected in sessions 3-4, showing differences between programmed and performed V_session and lower RI and velocity loss (VL) for the NAL compared to the AL group (p < 0.05). Although both groups improved 1RM, CMJ and T20, NAL experienced greater and significant changes than AL (28.90 vs.12.70%, 16.10 vs. 7.90% and -1.99 vs. -0.95%, respectively). Load adjustment based on movement velocity is a useful way to control for highly individualised responses to training and improve the implementation of RT programs.

Pre-exercise Caffeine Intake Enhances Bench Press Strength Training Adaptations

Previous research has identified acute caffeine intake as an effective ergogenic aid to enhance velocity and power during bench press exercise. However, no previous investigation has analyzed the effects of chronic intake of caffeine on training adaptations induced by bench press strength training. Thus, the aim of this investigation was to determine the effects of pre-exercise caffeine intake on training adaptations induced by a bench press training protocol. Using a double-blind, randomized experimental design, 16 healthy participants underwent a bench press training protocol for 4 weeks (12 sessions). Seven participants ingested a placebo and nine participants ingested 3 mg/kg/BM of caffeine before each training session. Three days before, and 3 days after the completion of the training protocol, participants performed a one-repetition maximum (1RM) bench press and force-velocity test (from 10 to 100% 1RM). From comparable pre-training values, the strength training similarly increased 1RM in the caffeine and placebo groups (+13.5 ± 7.8% vs. +11.3 ± 5.3%, respectively; p = 0.53). In the caffeine group, the strength training induced a higher mean velocity at 40%, (0.81 ± 0.08 vs. 0.90 ± 0.14 m/s), 60% (0.60 ± 0.06 vs. 0.65 ± 0.06 m/s), 70% (0.47 ± 0.05 vs. 0.55 ± 0.06 m/s), 80% (0.37 ± 0.06 vs. 0.45 ± 0.05 m/s), 90% (0.26 ± 0.07 vs. 0.34 ± 0.06 m/s), and 100% 1RM (0.14 ± 0.04 vs. 0.25 ± 0.05 m/s; p < 0.05) while the increases in the placebo group were evident only at 30 (0.95 ± 0.06 vs. 1.03 ± 0.07 m/s), 70% (0.51 ± 0.03 vs. 0.57 ± 0.05 m/s) and 80% 1RM (0.37 ± 0.06 vs. 0.45 ± 0.05 m/s) (p < 0.05). The placebo group only increased peak velocity at 60 and 70% 1RM (p < 0.05) while peak velocity increased at 10%, and from 30 to 100% 1RM in the caffeine group (p < 0.05). The use of 3 mg/kg/BM of caffeine before exercise did not modify improvements in 1RM obtained during a 4 week bench press strength training program but induced more muscle performance adaptations over a wider range of load.

The Validity and Reliability of Commercially Available Resistance Training Monitoring Devices: A Systematic Review

Background

Monitoring resistance training has a range of unique difficulties due to differences in physical characteristics and capacity between athletes, and the indoor environment in which it often occurs. Traditionally, methods such as volume load have been used, but these have inherent flaws. In recent times, numerous portable and affordable devices have been made available that purport to accurately and reliably measure kinetic and kinematic outputs, potentially offering practitioners a means of measuring resistance training loads with confidence. However, a thorough and systematic review of the literature describing the reliability and validity of these devices has yet to be undertaken, which may lead to uncertainty from practitioners on the utility of these devices.

Objective

A systematic review of studies that investigate the validity and/or reliability of commercially available devices that quantify kinetic and kinematic outputs during resistance training.

Methods

Following PRISMA guidelines, a systematic search of SPORTDiscus, Web of Science, and Medline was performed; studies included were (1) original research investigations; (2) full-text articles written in English; (3) published in a peer-reviewed academic journal; and (4) assessed the validity and/or reliability of commercially available portable devices that quantify resistance training exercises.

Results

A total of 129 studies were retrieved, of which 47 were duplicates. The titles and abstracts of 82 studies were screened and the full text of 40 manuscripts were assessed. A total of 31 studies met the inclusion criteria. Additional 13 studies, identified via reference list assessment, were included. Therefore, a total of 44 studies were included in this review.

Conclusion

Most of the studies within this review did not utilise a gold-standard criterion measure when assessing validity. This has likely led to under or overreporting of error for certain devices. Furthermore, studies that have quantified intra-device reliability have often failed to distinguish between technological and biological variability which has likely altered the true precision of each device. However, it appears linear transducers which have greater accuracy and reliability compared to other forms of device. Future research should endeavour to utilise gold-standard criterion measures across a broader range of exercises (including weightlifting movements) and relative loads.

Electronic supplementary material

The online version of this article (10.1007/s40279-020-01382-w) contains supplementary material, which is available to authorized users.

Velocity Loss Thresholds Reliably Control Kinetic and Kinematic Outputs during Free Weight Resistance Training

Exercise velocity and relative velocity loss thresholds (VLTs) are commonly used in velocity-based resistance training. This study aims to quantify the between-day reliability of 10%, 20%, and 30% VLTs on kinetic and kinematic outputs, changes in external load, and repetition characteristics in well-trained athletes. Using a repeated, counter-balanced crossover design, twelve semi-professional athletes completed five sets of the back squat with an external load corresponding to a mean concentric velocity of ~0.70 m·s^-1 and a VLT applied. The testing sessions were repeated after four weeks of unstructured training to assess the long-term reliability of each VLT. A coefficient of variation (CV) <10% was used to classify outputs as reliable. Kinetic and kinematic outputs and external load were largely reliable, with only peak power during sets 2-5 within the 10% VLT condition demonstrating a CV >10% (CV: 11.14-14.92%). Alternatively, the repetitions completed within each set showed large variation (CV: 18.92-67.49%). These findings demonstrate that by utilizing VLTs, kinetic and kinematic outputs can be prescribed and replicated across training mesocycles. Thus, for practitioners wishing to reliably control the kinetic and kinematic stimulus that is being applied to their athletes, it is advised that a velocity-based approach is used.

The Reliability and Validity of Current Technologies for Measuring Barbell Velocity in the Free-Weight Back Squat and Power Clean

This study investigated the inter-day and intra-device reliability, and criterion validity of six devices for measuring barbell velocity in the free-weight back squat and power clean. In total, 10 competitive weightlifters completed an initial one repetition maximum (1RM) assessment followed by three load-velocity profiles (40–100% 1RM) in both exercises on four separate occasions. Mean and peak velocity was measured simultaneously on each device and compared to 3D motion capture for all repetitions. Reliability was assessed via coefficient of variation (CV) and typical error (TE). Least products regression (LPR) (R²) and limits of agreement (LOA) assessed the validity of the devices. The Gymaware was the most reliable for both exercises (CV < 10%; TE < 0.11 m·s⁻¹, except 100% 1RM (mean velocity) and 90‒100% 1RM (peak velocity)), with MyLift and PUSH following a similar trend. Poorer reliability was observed for Beast Sensor and Bar Sensei (CV = 5.1–119.9%; TE = 0.08–0.48 m·s⁻¹). The Gymaware was the most valid device, with small systematic bias and no proportional or fixed bias evident across both exercises (R² > 0.42–0.99 LOA = −0.03–0.03 m·s⁻¹). Comparable validity data was observed for MyLift in the back squat. Both PUSH devices produced some fixed and proportional bias, with Beast Sensor and Bar Sensei being the least valid devices across both exercises (R² > 0.00–0.96, LOA = −0.36–0.46 m·s⁻¹). Linear position transducers and smartphone applications could be used to obtain velocity-based data, with inertial measurement units demonstrating poorer reliability and validity.

Effect of different interset rest intervals on mean velocity during the squat and bench press exercises

This study aimed to compare the effect of three interset rest intervals (1, 3, and 5 minutes) on (I) mean velocity during a resistance training session conducted in a Smith machine with the squat and bench press exercises, and (II) the pre- and post-exercise force-velocity relationship. Fifteen male university students completed three sessions (i.e., Rest 1', Rest 3', and Rest 5') consisting of three sets of five repetitions against the 10RM load during the squat and bench press exercises. The force-velocity relationship (maximal values of force [F₀], velocity [v₀], and power [P_max]) was evaluated at the beginning and at the end of each session with the countermovement jump and bench press throw exercises. During training, mean velocity was slower in sets 2 and 3 of the Rest 1' protocol compared to Rest 3' and Rest 5', but no significant differences were present between Rest 3' and Rest 5'. After training, there was a significant decrease in F₀ (p = 0.017) and P_max (p = 0.010), but not in v₀ (p = 0.259). These results support the Rest 3' as the most time-efficient protocol, among those analysed, for the maintenance of high mean velocities during training sessions not leading to failure.

Effect of Traditional, Cluster, and Rest Redistribution Set Configurations on Neuromuscular and Perceptual Responses During Strength-Oriented Resistance Training

Cuevas-Aburto, J, Jukic, I, Chirosa-Ríos, LJ, González-Hernández, JM, Janicijevic, D, Barboza-González, P, Guede-Rojas, F, and García-Ramos, A. Effect of traditional, cluster, and rest redistribution set configurations on neuromuscular and perceptual responses during strength-oriented resistance training. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to compare the acute effect of traditional (TR), cluster (CL), and rest redistribution (RR) set configurations on neuromuscular and perceptual measures of fatigue. Thirty-one resistance-trained men randomly performed a Control session and 3 experimental sessions consisting of the squat (SQ) and bench press (BP) exercises performed against the 10 repetition maximum load using TR (3 sets of 6 repetitions; 3 minutes of interset rest), CL (3 sets of 6 repetitions; 30 seconds of intraset rest every 2 repetitions; 3 minutes of interset rest), and RR (9 sets of 2 repetitions; 45 seconds of interset rest) set configurations. A significant effect of "set configuration" (p = 0.002) was observed for barbell velocity. The average velocity of the training session was lower for TR compared with CL (% difference = 5.09% in SQ and 5.68% in BP) and RR (% difference = 5.92% in SQ and 2.71% in BP). The 3 set configurations induced comparable decrements in countermovement jump height (% difference from -6.0% to -8.1%) and throwing velocity (% difference from -0.6% to -1.2%). Ratings of perceived exertion (RPE-10) values collected after the sets were higher for TR (SQ: 6.9 ± 0.7 a.u.; BP: 6.8 ± 0.8 a.u.) compared with CL (SQ: 6.2 ± 0.8 a.u.; BP: 6.4 ± 0.7 a.u.) and RR (SQ: 6.2 ± 0.8 a.u.; BP: 6.6 ± 0.9 a.u.), while the session RPE did not differ between the set configurations (p = 0.595). CL and RR set configurations allow for higher velocities and lower RPE values during resistance training sessions not performed to failure in comparison with a TR set configuration.

Reliability and Validity of Using the Push Band v2.0 to Measure Repetition Velocity in Free-Weight and Smith Machine Exercises

Hughes, LJ, Peiffer, JJ, and Scott, BR. Reliability and validity of using the Push Band v2.0 to measure repetition velocity in free-weight and Smith machine exercises. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate the test-retest reliability and concurrent validity of using the Push Band device 2.0 (PUSH) to quantify repetition velocity across 4 common resistance training exercises performed using free-weight and Smith machine training modalities. Twenty well-trained men (age: 25.1 ± 2.9 years, height: 182.4 ± 6.0 cm, body mass: 77.9 ± 12.0 kg, training age: 5.2 ± 1.4 years) visited the laboratory on 6 occasions (3 free-weight and 3 Smith machine sessions). Baseline strength assessments were conducted in the first session with each modality for squat, bench press, overhead press, and prone row exercises. The subsequent sessions featured repetitions performed with 30, 60, and 90% 1-repetition maximum. During these sessions, velocity was measured simultaneously using a validated linear position transducer (LPT; considered the criterion for this study) and 2 PUSH devices, one in body mode (PUSHBODY) and the other bar mode (PUSHBAR). Test-retest reliability was examined using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). The LPT demonstrated slightly greater reliability (ICC = 0.80-0.98, CV = 0.4-5.1%) than the PUSHBODY (ICC = 0.65-0.95, CV = 0.8-6.9%) and PUSHBAR (ICC = 0.50-0.93, CV = 0.7-7.1%) devices. Near-perfect correlations existed between velocity measured using LPT and PUSH devices (r = 0.96-0.99). No significant differences existed between mean velocity measures obtained using LPT and either PUSH device. The PUSH device can be used in either bar or body mode to obtain reliable and valid repetition velocity measures across a range of loads and exercises performed using either free weights or a Smith machine.

Movement velocity can be used to estimate the relative load during the bench press and leg press exercises in older women

Background

Movement velocity has been proposed as an effective tool to prescribe the load during resistance training in young healthy adults. This study aimed to elucidate whether movement velocity could also be used to estimate the relative load (i.e., % of the one-repetition maximum (1RM)) in older women.

Methods

A total of 22 older women (age = 68.2 ± 3.6 years, bench press 1RM = 22.3 ± 4.7 kg, leg press 1RM = 114.6 ± 15.9 kg) performed an incremental loading test during the free-weight bench press and the leg press exercises on two separate sessions. The mean velocity (MV) was collected with a linear position transducer.

Results

A strong linear relationship between MV and the relative load was observed for the bench press (%1RM = −130.4 MV + 119.3; r² = 0.827, standard error of the estimate (SEE) = 6.10%1RM, p < 0.001) and leg press exercises (%1RM = −158.3 MV + 131.4; r² = 0.913, SEE = 5.63%1RM, p < 0.001). No significant differences were observed between the bench press and leg press exercises for the MV attained against light-medium relative loads (≤70%1RM), while the MV associated with heavy loads (≥80%1RM) was significantly higher for the leg press.

Conclusions

These results suggest that the monitoring of MV could be useful to prescribe the loads during resistance training in older women. However, it should be noted that the MV associated with a given %1RM is significantly lower in older women compared to young healthy individuals.

Validity of the iLOAD® app for resistance training monitoring

Background

This study aimed (I) to assess the inter-rater agreement for measuring the mean velocity (MV) of the barbell with the iLOAD® app, and (II) to compare the magnitude of the MV and total work of a training session between the iLOAD® app and a linear encoder (reference method).

Method

Sixteen young healthy individuals (four women and 12 men) were tested in two sessions separated by 48 h. The 10 repetition maximum (RM) load was determined in the first testing session in the half squat exercise. The second testing session consisted of 3 sets of 10 repetitions during the half squat exercise performed against the 10RM load. Both the iLOAD® app and a linear encoder were used to calculate the MV and total work of each training set. MV was recorded with the iLOAD® app by two independent researchers to evaluate the inter-rater agreement.

Results

Trivial differences and nearly perfect correlations were observed between raters for the MV values collected under individual sets (effect size [ES] ≤ 0.02, r ≥ 0.987), as well as for the whole training session (ES = 0.01, r = 0.997). Trivial-small differences and nearly perfect correlations were observed between the iLOAD® app and the linear encoder (Chronojump, Barcelona, Spain) for MV (EV ≤ 0.25, r ≥ 0.903) and total work (ES ≤ 0.05, r ≥ 0.973). Bland-Altman plots did not reveal heteroscedasticity of the errors between the iLOAD® app and the linear encoder for MV (r² = 0.010) and total work (r² < 0.001).

Conclusions

iLOAD® is a valid smartphone app which can provide real-time feedback of the MV and total work completed in a set of multiple repetitions in the half squat exercise.