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Correlation with first order regression line between the linear transducer (LT) and: (A) Beast sensor (wrist, BW); (B) Beast sensor (barbell, BB); (C) PowerLift app for the hip-thrust exercise.
Source publication
The purpose of this study was to analyze the validity, reliability, and accuracy of new wearable and smartphone-based technology for the measurement of barbell velocity in resistance training exercises. To do this, 10 highly trained powerlifters (age = 26.1 ± 3.9 years) performed 11 repetitions with loads ranging 50–100% of the 1-Repetition maximum...
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Citations
... Carlos Balsalobre-Fernández, Madrid, Spain) (Balsalobre-Fernández et al. 2017), based on the force load-velocity relationship (González-Badillo and Sánchez-Medina 2010). This app has been proved to be highly valid, reliable, and accurate for the measurement of barbell velocity in the squat exercise(Balsalobre- Fernández et al. 2017). Participants performed an standardized warm-up(Peinado et al. 2021). ...
Purpose
To investigate the acute effects of eccentric-based resistance exercise and sex-hormone fluctuations on P1NP and β-CTX-1 concentrations in premenopausal females.
Methods
Nine eumenorrheic females and ten oral contraceptive (OC) users performed eccentric-based resistance exercise, consisted of 10 × 10 repetitions of parallel back squats with a 4-s eccentric phase, in the early-follicular (EFP), late-follicular (LFP) and mid-luteal (MLP) phases of the menstrual cycle (MC) or in the withdrawal (WP) and active pill-taking (APP) phases of the OC cycle.
Results
17β-oestradiol (pg·ml⁻¹) was lower in EFP (36.63 ± 29.93) compared to LFP (224.81 ± 233.81; p ≤ 0.001) and MLP (161.45 ± 110.08; p < 0.001) and higher in WP (24.857 ± 29.428) compared to APP (12.72 ± 13.36; p = 0.004). Progesterone (ng·ml-1) was higher in MLP (8.30 ± 5.23) compared to EFP (0.33 ± 0.33; p < 0.001) and LFP (0.21 ± 0.18; p < 0.001), no significant differences were observed between the WP and APP. In eumenorrheic females, β-CTX-1 (ng·ml⁻¹) was lower in MLP (0.395 ± 0.126) compared to LFP (0.472 ± 0.137; p = 0.044). Comparing MC vs OC phases, eumenorrheic females had higher P1NP levels (ng·ml⁻¹) compared to OC users: EFP (62.54 ± 13.13) vs APP (50.69 ± 8.91; p = 0.034), LFP (67.32 ± 18.96) vs WP (52.16 ± 10.72; p = 0.047), LFP vs APP (p = 0.025), MLP (67.51 ± 19.34; p = 0.049) vs WP, MLPvsAPP (p = 0.027). Exercise time effect showed lower β-CTX-1 concentrations 2 h post-exercise (MC: 0.376 ± 0.114, p < 0.001; OC: 0.340 ± 0.156, p = 0.030) compared to pre-exercise (MC: 0.485 ± 0.137; OC: 0.428 ± 0.188) in all participants.
Conclusions
β-CTX-1 concentrations were lower in the mid-luteal phase, emphasising the importance of standardizing bone marker measurements to a specific MC phase. OC users exhibited reduced P1NP levels, underscoring the need to investigate synthetic and endogenous hormones’ impact on long-term bone structure and strength.
Trial registration The study was registered at Clinicaltrials.gov NCT04458662 on 2 July 2020.
... Previous validation studies of SAs that measure barbell velocity have mainly concentrated on the app MyLift, formerly known as PowerLift. These studies have yielded inconclusive results, with some supporting its accuracy and reliability [3,[13][14][15] while others concluded that it is highly prone to error [16][17][18]. Another problem which seems to be more specific to SAs are missed repetitions and ghost repetitions. ...
The aim of this study was to determine the validity of three smartphone applications measuring barbell movement velocity in resistance training and comparing them to a commercially available linear transducer. Twenty competitive powerlifters (14 male and 6 female) completed a progressive loading protocol in the squat, bench press and deadlift (sumo or conventional) until reaching 90% of the highest load they had achieved in a recent competition. Mean velocity was concurrently recorded with three smartphone applications: Qwik VBT (QW), Metric VBT (MT), MyLift (ML), and one linear transducer: RepOne (RO). 3D motion capturing (Vicon) was used to calculate specific gold standard trajectory references for the different systems. A total of 589 repetitions were recorded with a mean velocity of (mean ± standard deviation [min-max]) 0.44 ± 0.17 [0.11–1.04] m·s⁻¹, of which MT and ML failed to identify 52 and 175 repetitions, respectively. When compared to Vicon, RO and QW consistently delivered valid measurements (standardized mean bias [SMB] = 0 to 0.21, root mean squared error [RMSE] = 0.01 to 0.04m·s⁻¹). MT and ML failed to deliver a level of validity comparable to RO (SMB = -0.28 to 0.14, RMSE = 0.04–0.14m·s⁻¹), except for MT in the bench press (SMB = 0.07, RMSE = 0.04m·s⁻¹). In conclusion, smartphone applications can be as valid as a linear transducer when assessing mean concentric barbell velocity. Out of the smartphone applications included in this investigation, QW delivered the best results.
... The barbell acceleration and velocity at the 2 nd pull phase were estimated using the sensor on the forearm. Since the previous study measured the barbell velocity using the wrist IMU sensor during the resistance training exercises (Balsalobre-Fernández et al., 2017). ...
... To eliminate this error, we performed each lift separately during the experiment. The barbell velocity and acceleration were estimated from the sensor on the forearm in a previous study (Balsalobre-Fernández et al., 2017). The data were calculated at the end of the 2 nd pull phase before the excessive elbow rotation that occurred during the turnover phase to avoid the measurement error. ...
... Compared to previous studies which assessed the validity of other portable and wearable devices (i.e., PUSH Band, Beast Sensor), Polar Verity Sense showed similar or better validity for measuring these variables during the bench press exercise (Lake et al., 2019;Perez-Castilla et al., 2019;van den Tillaar & Ball, 2019). However, some devices, such as linear position transducers (i.e., GymAware Power Tool) did show better validity in measuring velocity (Balsalobre-Fernández et al., 2017;Dorrell et al., 2018). This can be due to the fact that linear position transducers directly measure velocity through linear position displacement (Garnacho-Castaño et al., 2015), while accelerometers integrated into Polar Verity Sense estimate velocity by integrating the acceleration signal over time, thus displaying greater susceptibility to noise and integration error (Zhu & Lamarche, 2007). ...
The assessment of force, velocity, and power is useful in order to develop an athlete's sports performance and avoid any possible injuries. The aim of this study is to assess concurrent validity by using Polar Verity Sense with Motion X-Ray technology in order to measure velocity, force, and power in bench press exercises and compare them with the golden standard (i.e., Qualisys 3D kinematics). This pilot study focused on three male recreational lifters aged 28, with between five and ten years of experience, and a 1RM bench press of 100kg. The procedure lasted for two days. On the first day, 1 RM was assessed on a Smith machine. After seven days, the participants performed two sets of seven bench press repetitions with a 50kg bar on the same machine. The first set was a trial, and the second was analysed. The collected data was analysed using the Polar Verity sensor with Motion X-Ray technology, and 3D kinematic analysis with Qualysis. There were no significant statistical differences between these two systems (p < 0.05), while Pearson correlation showed a high and significant correlation between them (r > 0.692 < 0.999; p < 0.05). This research sets the basis of a new measurement process, which will be easier and more affordable. Future research could focus on bigger research samples, different types of exercise, and faster movements.
... To optimize such elements, fencers must cultivate speed, agility, force, endurance, and an acute sense of balance and movement control through specific training. While extensive literature exists for the enhancement of speed and agility in general [21][22][23][24] and within the domain of fencing [25], the assessment and improvement of hand control [26,27], there is a conspicuous absence of tools or devices for measuring balance and movement control. ...
... Sensors 2023, 23, x FOR PEER REVIEW 2 of 18 and agility in general [21][22][23][24] and within the domain of fencing [25], the assessment and improvement of hand control [26,27], there is a conspicuous absence of tools or devices for measuring balance and movement control. Usually, IMUs are used for assessing injury risks, as in [9][10][11][12] and [14], while the proposed system is used to evaluate balance and movement control performance. ...
Fencing, a sport emphasizing the equilibrium and movement control of participants, forms the focal point of inquiry in the current study. The research endeavors to assess the efficacy of a novel system designed for real-time monitoring of fencers’ balance and movement control, augmented by modules incorporating visual feedback and haptic feedback, to ascertain its potential for performance enhancement. Over a span of five weeks, three distinct groups, each comprising ten fencers, underwent specific training: a control group, a cohort utilizing the system with a visual real-time feedback module, and a cohort using the system with a haptic real-time feedback module. Positive outcomes were observed across all three groups, a typical occurrence following a 5-week training regimen. However, noteworthy advancements were particularly discerned in the second group, reaching approximately 15%. In contrast, the improvements in the remaining two groups were below 5%. Statistical analyses employing the Wilcoxon signed-rank test for repeated measures were applied to assess the significance of the results. Significance was solely ascertained for the second group, underscoring the efficacy of the system integrated with visual real-time feedback in yielding statistically noteworthy performance enhancements.
... The one-repetition maximum has been the most widely used method for quantifying training intensity [4,5]. However, the main drawback of this approach is that it requires the performance of a maximal lift [3] or a number of repetitions with submaximal loads to failure [6,7]. Recently, many authors, based on the force-velocity relationship [8], have recommended the use of velocity feedback to quantify training loads [1,9,10]. ...
... This approach is based on a previously reported high correlation (R 2 > 0.97) between the load and the mean velocity at which each load is lifted [10][11][12]. 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 provide accurate, indirect estimations of the 1 RM without the need to perform a maximal lift [7,13,14]. It has been reported that barbell velocity during the bench press, back squat, and bench pull are highly correlated with training intensity in terms of %1RM [15][16][17][18]. ...
... Linear position transducers (LPTs) are often used for measuring velocity in resistance exercises through a vertical displacement of a cable that is attached to the barbell [27,28]. In some studies, it has been reported that LPTs seem to be the most reliable and valid tool [7,21,29,30]. Recently, the GymAware linear transducer (GYM; Kinetic Performance Technologies, Canberra, Australia) has become increasingly popular in the monitoring of resistance training and optimisation of training prescriptions [31][32][33]. ...
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 force-velocity relationship has increasingly been used for training purposes [57,58]. This relationship would also be a good tool for assessing the consequences of fatigue [35,59], allowing for better control of loads and effort during training [60,61], particularly important for Paralympic powerlift thletes. ...
Background:
Paralympic powerlifting (PP) is performed on a bench press, aiming to lift as much weight as possible in a single repetition.
Purpose:
To evaluate thermal asymmetry and dynamic force parameters with 45 and 80% 1 Repetition Maximum (1 RM) in PP athletes.
Methods:
Twelve elite PP male athletes were evaluated before and after a training session regarding skin temperature (thermography) and dynamic force indicators (Average Propulsive Velocity-MPV, Maximum Velocity-VMax, and Power). The training consisted of five series of five repetitions (5 × 5) with 80% 1 RM. The force indicators and dynamics before and after (45% 1 RM) were evaluated in series "1" and "5" with 80% 1 RM.
Results:
The temperature did not present asymmetry, and there were differences between the moment before and after. In MPV, Vmax, and Power, with 45% 1 RM, there were differences both in asymmetry and in moments (p < 0.005). With 80% 1 RM, asymmetry was observed, but no differences between moments (p < 0.005).
Conclusion:
No thermal asymmetry was observed. There were reductions in MVP and VMax at 45 and 80% 1 RM but without significant differences between time points (before and after). However, there was asymmetry in the moments before and after within a safety standard, where Paralympic powerlifting was safe in terms of asymmetries.
... While linear position transducers (LPT) are reliable [7] and considered the gold standard for measuring barbell velocity, they are often too expensive for non-professional use [8][9][10]. Recent studies have therefore investigated the validity and reliability of more affordable technologies, such as cameras, smartphone apps, and wearables designed specifically for VBT [11][12][13]. However, a specific area of interest that has not been sufficiently explored is the potential use of consumer wearables capable of measuring barbell velocity for VBT, while also providing additional features (i.e., sleep tracking). ...
... Thus, the validity of commercially available IMUs for VBT monitoring is still discussed in the field. Multiple studies have assessed the validity of different IMU-based VBT devices such as the Beast Sensor (Beast Technologies S.r.l., Brescia, Italy), VmaxPro (BM Sports Technology GmbH, Magdeburg, Germany) and Push Band 2 (Whoop, Boston, MA, USA) [11,12,[17][18][19] in a variety of free weight and Smith machine-supported barbell exercises. No definitive conclusion has yet been drawn, thus highlighting the need for further investigation. ...
... The study design was developed to assess the validity of the Apple Watch 7 s IMU sensor during free-weighted back squats in healthy volunteers. The methodology employed in this study was similar to previous validation studies [8,11]. All participants gave written signed consent prior to any data acquisition. ...
Velocity-based training (VBT) is a method to monitor resistance training based on measured kinematics. Often, measurement devices are too expensive for non-professional use. The purpose of this study was to determine the accuracy and precision of the Apple Watch 7 and the Enode Pro device for measuring mean, peak, and propulsive velocity during the free-weighted back squat (in comparison to Vicon as the criterion). Velocity parameters from Vicon optical motion capture and the Apple Watch were derived by processing the motion data in an automated Python workflow. For the mean velocity, the barbell-mounted Apple Watch (r = 0.971–0.979, SEE = 0.049), wrist-worn Apple Watch (r = 0.952–0.965, SEE = 0.064) and barbell-mounted Enode Pro (r = 0.959–0.971, SEE = 0.059) showed an equal level of validity. The barbell-mounted Apple Watch (Vpeak: r = 0.952–0.965, SEE = 0.092; Vprop: r = 0.973–0.981, SEE = 0.05) was found to be the most valid for assessing propulsive and peak lifting velocity. The present results on the validity of the Apple Watch are very promising, and may pave the way for the inclusion of VBT applications in mainstream consumer wearables.
... Natural antioxidants derived from foods have been studied and believed to have protective biological functions in preventing stress induce diseases and cell damage due to free radicals (Balsalobre-Fernández et al., 2017). Milk, in particular, contains proteins with varied biological functions, and caseins are the major protein of ovine and bovine milks, which is present in the form of macromolecular aggregates. ...
It is generally established that oxidative stress has a role in the etiology of diseases linked to the lifestyle, such as cancer, aging, diabetes mellitus, and neurological diseases, among others. This research aims to evaluate the effect of casein on the survival rate and oxidative stress markers in Drosophila melanogaster. 360 flies were divided into four groups, each containing 90 flies (30 flies in triplicate). The groups include:1) the control group; 2) the HR 2 ROR 2 R treated group; 3) the HR 2 ROR 2 R induced + 1% Casein group; 4) the 1% Casein only group. Oxidative stress was induced in the flies and 1% Casein was used to protect the flies through enrichment of their diet and the effect of stress and Casein treatment was monitored on the mortality rate of the flies and selected oxidative stress markers. The results revealed that HR 2 ROR 2 Rsignificantly decreases the survival rate, GSH, total thiol and total protein while it increases the level of MDA, SOD and CAT. However, treatment with 1% Casein significantly reverses the effect of HR 2 ROR 2 R on the oxidative stress biomarkers and increases flies' survival rate. In conclusion, Casein may increase the survival rate of the fruit flies under stress and modulate stress biomarkers via possible binding of the peptides AS29, AS14, K009, and K010 to the Keap1/Nrf2 signaling pathway. The oxidation process is thought to be the primary cause of human aging, degenerative diseases, and stress related diseases. Casein is a protein found in mammalian milk that accounts for roughly 20 to 60% of the proteins in human milk and 80% of the proteins in cow's milk. It represents a good source of antioxidants and bioactive peptides making it a promising candidate for preventing harmful stress, aging, immune boosting and preventing/treating disorders associated with oxidative stress.
... Therefore, systems based on the inertial measurement unit (IMU) [24,25], camera [26], laser rangefinder [27], and linear position transducer (LPT) [28][29][30] were widely used in those scenarios because of their convenience and low cost [31][32][33]. Among the above systems, the LPT-based system was considered the most valid and reliable measurement system [29,[34][35][36]. ...
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 visuali-zation 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 Pear-son'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.
