Low-intensity training with blood flow restriction (LI-BFR) has been suggested as an alternative to high-intensity resistance training for the improvement of strength and muscle mass, becoming advisable for individuals who cannot assume such a load. The systematic review aimed to determine the effectiveness of the LI-BFR compared to dynamic high-intensity resistance training on strength and muscle mass in non-active older adults. A systematic review was conducted according to the Cochrane Handbook and reportedly followed the PRISMA statement. MEDLINE, EMBASE, Web of Science Core Collection, and Scopus databases were searched between September and October 2020. Two reviewers independently selected the studies, extracted data, assessed the risk of bias and the quality of evidence using the GRADE approach. Twelve studies were included in the qualitative synthesis. Meta-analysis pointed out significant differences in maximal voluntary contraction (MVC): SMD 0.61, 95% CI [0.10, 1.11], p = 0.02, I² 71% p < 0.0001; but not in the repetition maximum (RM): SMD 0.07, 95% CI [−0.25, 0.40], p = 0.66, I² 0% p < 0.53; neither in the muscle mass: SMD 0.62, 95% CI [−0.09, 1.34], p = 0.09, I² 59% p = 0.05. Despite important limitations such as scarce literature regarding LI-BFR in older adults, the small sample size in most studies, the still differences in methodology and poor quality in many of them, this systematic review and meta-analysis revealed a positive benefit in non-active older adults. LI- BFR may induce increased muscular strength and muscle mass, at least at a similar extent to that in the traditional high-intensity resistance training.

Background: Velocity-based training (VBT) requires precise measurement devices to monitor neuromuscular performance. PowerTrack^TM is a novel optoelectronic device designed to assess movement velocity in resistance training. This study aimed to evaluate the validity and reliability of PowerTrack^TM during the Smith machine back squat. Methods: Twenty experienced-trained men performed three repetitions at three submaximal loads (20, 50, and 70 kg) across two sessions. Velocity metrics—mean velocity (MV), mean propulsive velocity (MPV), and maximum velocity (Vmax)—were simultaneously recorded by PowerTrack^TM and the criterion device (MuscleLab^TM). Validity was assessed via ordinary least products (OLP) regression, Lin’s concordance correlation coefficient (CCC), and Bland–Altman plots. Reliability was determined using intraclass correlation coefficients (ICCs), standard error of measurement (SEM), coefficient of variation (CV), and minimum detectable change (MDC). Results: PowerTrack showed high agreement with MuscleLab^TM for MPV and Vmax (slope ≈ 1.00; CCC = 0.95–0.97), while MV presented a proportional bias (slope = 0.83). ICCs ranged from 0.78 to 0.91 across loads, and SEM remained <0.09 m/s for all metrics, indicating excellent relative reliability and acceptable absolute precision. Conclusion: Despite a slight underestimation of MV at light loads, PowerTrack^TM proved to be a valid and reliable device for velocity monitoring in VBT contexts.

Background: Velocity loss (VL) is widely used in velocity-based training (VBT) to index mechanical fatigue, yet attentional focus cues may alter velocity profiles and their relationship with internal load. This study tested whether internal focus, external focus, or control modifies repetition-level velocity, lactate kinetics, and lactate–VL% coupling during bench press (BP) at 60% one-repetition maximum (1RM). Methods: Thirty-six trained men were randomized into three groups. Thirty-four participants completed the study and were included in the final analyses according to outcome-specific data availability. Participants completed two counterbalanced sessions on a Smith machine BP: (i) a single set to technical failure, and (ii) a conventional 3 sets × 10 repetitions at 60% 1RM. Concentric velocity was recorded via a linear position transducer and analyzed at the repetition level using linear mixed-effects models. Lactate was analyzed via Gaussian generalized estimating equations (GEEs). Results: Repetitions to failure and terminal velocity at failure did not differ between groups (Welch p = 0.328; ω² = 0.045). During 3 sets × 10 repetitions, velocity decreased across sets and repetitions (both p < 0.001); adding group terms improved fit (LR χ²(12) = 42.26, p < 0.001), with additional improvement for group-dependent fatigue patterns (LR χ²(6) = 14.90, p = 0.021). Lactate increased over time (Wald χ²(4) = 244.56, p < 0.001) with convergence by post-lactate set 3 and post-lactate 30 s. Lactate–VL% coupling was strongly moderated by group (post-lactate × group: χ²(2) = 80.42, p < 0.001), with slopes (ΔVL% per 1 mmol·L⁻¹) of 5.27 (internal focus), 13.60 (external focus), and 0.04 (control). After Holm correction across prespecified primary outcomes, only the post-session rating of perceived exertion differed (pHolm = 0.004; ω² = 0.045), with higher values in the external focus group. Pairwise effects were calculated as comparator minus external focus; therefore, negative g values indicate a higher rate of perceived exertion (RPE) in the external focus group (gHedges ≈ −1.50 vs. control; −1.37 vs. internal focus). Conclusions: Attentional cueing did not consistently alter averaged VL% outcomes after multiplicity correction, but it was associated with differences in early lactate kinetics and modified the observed association between post-set lactate and VL% in the interaction-based coupling model. Cueing scripts should therefore be reported verbatim and standardized in VBT studies, particularly when VL-derived indices are interpreted alongside internal load markers.

Background: Accurate monitoring of eccentric phase velocity is needed to support velocity-based training (VBT), yet field-valid tools for multi-joint exercises are scarce. This study evaluated the concurrent validity and reliability of an optoelectronic device to quantify eccentric phase velocity during the Smith machine back squat. Methods: A total of 20 resistance-trained men completed two sessions and performed three repetitions at three submaximal loads (20, 50, and 70 kg). Eccentric mean velocity and peak velocity (Vmax) were recorded simultaneously using PowerTrack^TM and a criterion system (MuscleLab^TM). Validity was assessed using ordinary least products regression, Lin’s concordance correlation coefficient (CCC), and Bland–Altam analysis. Reliability was examined via intraclass correlation coefficients (ICC), standard error of measurement (SEM), coefficient of variation, and minimum detectable change. Results: Agreement between devices was very high for Vmax (slope ≈ 1.00; CCC = 0.95), with a small constant bias. Eccentric mean velocity showed proportional bias under higher velocity conditions, whereas overall concordance remained high (CCC = 0.95). Inter-session reliability was excellent (ICC = 0.87–0.96), with low SEM values for eccentric velocity metrics. Conclusions: PowerTrack^TM can be a valid and reliable tool for monitoring eccentric phase velocity during the Smith machine back squat, with Vmax representing the most robust metric for applied eccentric VBT.

Tendinopathy is a prevalent degenerative condition characterized by collagen disorganization, pain, and impaired function. High-load resistance training (HL-RT) is the current standard for promoting tendon adaptation; however, it may not be feasible for all patients. Low-load blood flow restriction training (LL-BFRT) has emerged as a potential alternative that may allow exercise to be performed with lower mechanical loads. The objective was to explore the effects of LL-BFRT on tendon morphology and functional outcomes in individuals with tendinopathy and to identify common training parameters and limitations in the current literature. An exploratory review was conducted, with the study selection process reported using the PRISMA 2020 framework. Databases were searched (Jan 2020–May 2025) for studies assessing LL-BFRT in adult patients. Eligible study designs included randomized controlled trials, feasibility studies, case reports, and case series. Nine studies met the inclusion criteria: 4 randomized controlled trials (RCTs), 1 feasibility study, 1 case series, and 3 case reports. Improvements in pain, muscle strength, and patient-reported functional outcomes were reported across several tendinopathy types, including patellar, lateral elbow, rotator cuff, and gluteal tendinopathy. Ultrasound findings showed inconsistent changes in tendon morphology, with some studies reporting changes in tendon thickness or vascularity. Functional gains were observed even in the absence of morphological changes. Protocols commonly used low-load exercise performed 2–4 sessions per week, although occlusion pressure, exercise volume, and intervention duration varied across studies. No serious adverse events were reported. Heterogeneity in training parameters, small sample sizes, and lack of long-term follow-up limit generalizability. LL-BFRT may have potential for improving functional outcomes in tendinopathy rehabilitation, although the limited and heterogeneous evidence precludes firm conclusions regarding its clinical effectiveness and safety. Further high-quality RCTs with standardized protocols are needed to establish its clinical efficacy and characterize tendon-specific adaptations. Highlights Low-load blood flow restriction training (LL-BFRT) was associated with improvements in pain and functional outcomes across several studies in individuals with tendinopathy. Tendon morphological responses to LL-BFRT remain unclear, with limited and heterogeneous evidence across the included studies. LL-BFRT may represent a useful low-load rehabilitation approach when high mechanical loads are not well tolerated, although further high-quality research is required.