Load-velocity relationship in the horizontal leg-press exercise in older women and men

Acute and time-course changes in hemodynamic and physical performance parameters following single and multiple resistance training sets in cognitively impaired individuals: A randomized crossover study

This study analyzed the acute and time-course changes following one resistance training (RT) set (1SET) and three sets (3SET) on hemodynamic and physical performance parameters in individuals with different cognitive impairment levels. Thirty-nine individuals (22 women and 17 men aged 80 ± 9 years) grouped by cognitive impairment (mild [MILD], moderate [MOD], and severe [SEV]) randomly performed two protocols, each separated by one week, of 1SET or 3SET of 10 repetitions. Before (PRE), immediately (POST), and 72 h after (POST72) protocols, the participants performed the following measurements: systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), 1-kg medicine ball throw (MBT) distance, five-repetition sit-to-stand (STS) time, and handgrip strength (HGS). A three-way ANOVA with repeated measures revealed no significant differences between 1SET and 3SET on SBP, DBP, HR, STS, MBT, and HGS in any group at any time (all p ≥ 0.05). SEV increased SBP and HR from PRE to POST and decreased STS time after 3SET. From POST to POST72, all groups decreased SBP after both protocols, and SEV improved STS time after 3SET and HGS following both protocols. Furthermore, from PRE to POST72, MILD decreased SBP, while SEV improved HGS following 1SET and STS time following 3SET. These findings demonstrate that single and multiple sets cause acute hemodynamic changes, with a tendency to reduce SBP within 72 h. Additionally, individuals with worse cognitive function showed greater adaptive responses over time in physical performance, with 1SET improving HGS and 3SET enhancing STS performance. Trial registration: ClinicalTrials.gov ID: NCT06185010.

Validity and reliability of the T-Force and Chronojump systems to measure movement velocity on resistance machines with older adults

The current study aimed to analyze the validity and reliability of the T-Force and Chronojump systems to measure the movement velocity in the leg press (LP) and chest press (CP) exercises in older people. Eighteen older adults (6 men and 12 women, 79.9 ± 8.5 years) performed a set of procedures over three weeks: (i) the first week was to familiarize participants with the testing procedures, (ii) the second was to perform a progressive loading test until reaching one-repetition maximum (1RM) in the LP and CP, and (iii) in the third week, participants performed three repetitions against five loads (40, 50, 60, 70, and 80% of 1RM). The mean velocity of each repetition was recorded simultaneously through the T-Force and Chronojump devices. Linear regressions (coefficient of determination [r2] and standard error of the estimate [SEE]) analyzed the inter-device validity, and Bland-Altman plots illustrated the systematic differences between devices. A mixed-effects model estimated the mean velocity differences between devices. The relative reliability was analyzed by the intra-class correlation coefficient (ICC[1,k]), while the absolute reliability was by the standard error of measurement (SEM) and the coefficient of variation (CV). The results showed that the T-Force and Chronojump presented a high association level in measuring mean velocity in the LP and CP (r2 range: 0.96-0.99; SEE range: 0.01-0.02 m·s- 1) and low systematic bias (0.02-0.03 m·s- 1). The mean velocity values of T-Force were significantly higher than Chronojump only for 40% 1RM (p = 0.04). Excellent reliability inter-device (ICC range: 0.95-0.98; CV range: 1.7-3.2%) and intra-device (ICC range: 0.90-0.97; CV range: 3.4-6.5%) was observed. This study shows that the T-Force and Chronojump systems are valid and reliable for measuring movement velocity in the CP and LP machines when used by older adults.

Optimizing resistance training intensity in supportive care for survivors of breast cancer: velocity-based approach in the row exercise

PURPOSE

Resistance training mitigates side effects during and after cancer treatment. To provide a new approach for precisely and safely assessing and prescribing the intensity of resistance training in supportive cancer care, the purpose of this study was to evaluate the load-velocity relationship during the row exercise in women survivors of breast cancer.

METHODS

Twenty women survivors of breast cancer who had undergone surgery and had completed core breast cancer treatment within the previous 10 years completed an incremental loading test until the one repetition maximum (1RM) in the row exercise. The velocity was measured during the concentric phase of each repetition with a linear velocity transducer, and their relationship with the relative load was analyzed by linear and polynomial regression models.

RESULTS

A strong relationship was observed between movement velocity and relative load for all measured velocity variables using linear and polynomial regression models (R2 > 0.90; SEE < 6.00%1RM). The mean velocity and mean propulsive velocity of 1RM was 0.40 ± 0.03 m·s-1, whereas the peak velocity at 1RM was 0.64 ± 0.07 m·s1.

CONCLUSION

In women survivors of breast cancer, monitoring movement velocity during the row exercise can facilitate precise assessment and prescription of resistance training intensity in supportive cancer care.

Sex-related differences in the load-velocity and load-power relationships of the decline bench press exercise

The purpose of this study was to analyse the load-velocity and load-power relationships of the decline bench press exercise (DBPE) and to compare sex-related differences. Twelve young healthy men and women performed a progressive loading test for the determination of 1RM strength and individual load-velocity and load-power relationship in the DBPE. A very close relationship between mean propulsive velocity (MPV) and %1RM was observed (R2 = 0.94). This relationship improved when plotting data separately by sex (R2 = 0.96-97). Individual load-velocity profiles gave an R2 = 0.99 ± 0.01. The relationship between mean propulsive power (MPP) and %1RM was R2 = 0.23. When separating data by sex, R2 = 0.64-73 were obtained. Individual load-power profiles gave an R2 of 0.93 ± 0.07. Significant sex-related differences were found for MPV, with males having faster velocities than females from 30% to 40% 1RM (p = 0.01) and for MPP, with males having greater MPP (W) than females from 30% to 95% 1RM (p < 0.001). The results of this study show that a strong correlation exists between relative load and MPV/MPP in the DBPE, allowing the possibility of using one to predict the other with great precision, especially when a sex-specific equation is used.

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.

Changes in strength-related outcomes following velocity-monitored resistance training with 10 % and 20 % velocity loss in older adults

We compared the effects of velocity-monitored resistance training with an intra-set velocity loss (i.e., the decrement in repetition velocity over the set) of 10 % vs. 20 % on strength-related outcomes in older adults. We randomly assigned eighteen older adults to a velocity loss group of 10 % (n = 10; 78 ± 12 years) or 20 % (n = 8; 73 ± 10 years) to perform a 10-week training program. The primary outcomes were the one-repetition maximum (1RM) and the average mean velocity against absolute loads associated with loads <60 % 1RM (MVlow) and ≥ 60 % 1RM (MVhigh) in the leg and chest press exercises, assessed at pre-, mid- (week 5), and post-test. Secondary outcomes included handgrip strength, 1-kg medicine ball throw distance, 10-m walking time, and five-repetition sit-to-stand time. No differences between groups were found in any outcome at any time (p > 0.05). Both groups improved the 1RM leg press from pre- to mid- and post-test and the MVlow and MVhigh from pre- to mid-test (p < 0.05). No group improved the 1RM chest press (p > 0.05), but both increased the MVlow from pre- to mid-test (p < 0.05). Furthermore, both groups improved the sit-to-stand time, while only the 20 % velocity loss group significantly improved handgrip strength and 10-m walking time (p < 0.05). The results showed that both velocity losses improved leg press strength and velocity, chest press velocity, and sit-to-stand time in older adults, although a 10 % velocity loss was more efficient as it required less volume (i.e., total repetitions) than 20 %. Nevertheless, the latter seems required to optimize handgrip strength and 10-m walking time in older people.

Load-velocity Relationship of the Bench Press Exercise is not Affected by Breast Cancer Surgery and Adjuvant Therapy

We examined the effect of breast cancer surgery and adjuvant therapy on the relationship between bar velocity and relative intensity (load-velocity [L-V] relationship) of the bench press (BP) exercise. Twenty-two breast cancer survivors (age: 48.0±8.2 yr., relative strength: 0.40±0.08) completed a loading test up to the one-repetition maximum (1RM) in the BP using a lightweight carbon bar. General and individual relationships between relative intensity (%1RM) and mean propulsive velocity (MPV) were studied. Furthermore, the mean test velocity (MPVTest) and velocity attained to the 1RM (MPV1RM) were analyzed. These procedures and analyses were also conducted in 22 healthy women (age: 47.8±7.1 yr., relative strength: 0.41±0.09) to examine the differences in velocity parameters derived from these L-V relationships. Polynomial regressions showed very close relationships (R2≥0.965) and reduced estimation errors (≤4.9% 1RM) for both groups. Between-group differences in MPV attained to each %1RM were small (≤0.01 m·s-1) and not significant (p≥0.685). Similarly, the MPVTest (0.59±0.06 m·s-1) and MPV1RM (0.17±0.03 m·s-1) were identical for breast cancer survivors and healthy women. These results suggest that practitioners could use the same velocity parameters derived from the BP L-V relationship to prescribe this exercise in middle-aged women, regardless of whether they have suffered from breast cancer.

Should We Use the Men Load-Velocity Profile for Women in Deadlift and Hip Thrust?

Injuries are common in team sports and can impact both team and individual performance. In particular, hamstring strain injuries are some of the most common injuries. Furthermore, hamstring injury ratios, in number of injuries and total absence days, have doubled in the last 21 seasons in professional soccer. Weakness in hip extensor strength has been identified as a risk factor in elite-level sprinters. In addition, strength imbalances of the hamstring muscle group seem to be a common cause of hamstring strain injuries. In this regard, velocity-based training has been proposed to analyze deficits in the force-velocity profile. Previous studies have shown differences between men and women, since there are biomechanical and neuromuscular differences in the lower limbs between sexes. Therefore, the aim of this study was to compare the load-velocity profile between males and females during two of the most important hip extension exercises: the hip thrust and the deadlift. Sixteen men and sixteen women were measured in an incremental loading test following standard procedures for the hip thrust and deadlift exercises. Pearson's correlation (r) was used to measure the strength of the correlation between movement velocity and load (%1RM). The differences in the load-velocity relationship between the men and the women were assessed using a 2 (sex) × 15 (load) repeated-measures ANOVA. The main findings revealed that: (I) the load-velocity relationship was always strong and linear in both exercises (R² range: 0.88-0.94), (II) men showed higher velocities for light loads (30-50%1RM; effect size: 0.9-0.96) than women for the deadlift, but no significant differences were found for the hip thrust. Based on the results of this study, the load-velocity equations seem to be sex-specific. Therefore, we suggest that using sex-specific equations to analyze deficits in the force-velocity profile would be more effective to control intensity in the deadlift exercise.

Estimating the relative load from movement velocity in the seated chest press exercise in older adults

AIM

This study aimed to i) determine the load-velocity relationship in the seated chest press in older adults, ii) compare the magnitude of the relationship between peak and mean velocity with the relative load, and iii) analyze the differences between sexes in movement velocity for each relative load in the chest press.

MATERIAL AND METHODS

Thirty-two older adults (17 women and 15 men; 79.6±7.7 years) performed a chest press progressive loading test up to the one-repetition maximum (1RM). The fastest peak and mean velocity reached with each weight were analyzed. Quadratic equations were developed for both sexes and the effectiveness of the regression model was analyzed through a residual analysis. The equations were cross-validated, considering the holdout method. The independent samples t-test analyzed i) the differences in the magnitude of the relationship between peak and mean velocity with the relative load and ii) the differences between sexes in the peak and mean velocity for each relative load.

RESULTS

It was possible to observe very strong quadratic load-velocity relationships in the seated chest press in women (peak velocity: r2 = 0.97, standard error of the estimate (SEE) = 4.5% 1RM; mean velocity: r2 = 0.96, SEE = 5.3% 1RM) and men (peak velocity: r2 = 0.98, SEE = 3.8% 1RM; mean velocity: r2 = 0.98, SEE = 3.8% 1RM) without differences (p>0.05) in the magnitude of the relationship between peak and mean velocity with the relative load. Furthermore, there was no overfitting in the regression models due to the high and positive correlation coefficients (r = 0.98-0.99). Finally, men presented higher (p<0.001) lifting velocities than women in almost all relative loads, except for 95-100% 1RM (p>0.05).

CONCLUSION

Measuring repetition velocity during the seated chest press is an objective approach to estimating the relative load in older adults. Furthermore, given the velocity differences between older women and men at submaximal loads, it is recommended to use sex-specific equations to estimate and prescribe the relative loads in older adults.

Load-power relationship in older adults: The influence of maximal mean and peak power values and their associations with lower and upper-limb functional capacity

Identifying the relative loads (%1RM) that maximize power output (Pmax-load) in resistance exercises can help design interventions to optimize muscle power in older adults. Moreover, examining the maximal mean power (MPmax) and peak power (PPmax) values (Watts) would allow an understanding of their differences and associations with functionality markers in older adults. Therefore, this research aimed to 1) analyze the load-mean and peak power relationships in the leg press and chest press in older adults, 2) examine the differences between mean Pmax-load (MPmax-load) and peak Pmax-load (PPmax-load) within resistance exercises, 3) identify the differences between resistance exercises in MPmax-load and PPmax-load, and 4) explore the associations between MPmax and PPmax in the leg press and chest press with functional capacity indicators. Thirty-two older adults (79.3 ± 7.3 years) performed the following tests: medicine ball throw (MBT), five-repetition sit-to-stand (STS), 10-m walking (10 W), and a progressive loading test in the leg press and chest press. Quadratic regressions analyzed 1) the load-mean and peak power relationships and identified the MPmax-load, MPmax, PPmax-load, and PPmax in both exercises, 2) the associations between MPmax and PPmax in the chest press with MBT, and 3) the associations between MPmax and PPmax in the leg press with STSpower and 10Wvelocity. In the leg press, the MPmax-load was ∼66% 1RM, and the PPmax-load was ∼62% 1RM, both for women and men (p &gt; 0.05). In the chest press, the MPmax-load was ∼62% 1RM, and the PPmax-load was ∼56% 1RM, both for women and men (p &gt; 0.05). There were differences between MPmax-load and PPmax-load within exercises (p &lt; 0.01) and differences between exercises in MPmax-load and PPmax-load (p &lt; 0.01). The MPmax and PPmax in the chest press explained ∼48% and ∼52% of the MBT-1 kg and MBT-3 kg variance, respectively. In the leg press, the MPmax and PPmax explained ∼59% of STSpower variance; however, both variables could not explain the 10Wvelocity performance (r2 ∼ 0.02). This study shows that the Pmax-load is similar between sexes, is resistance exercise-specific, and varies within exercises depending on the mechanical power variable used in older adults. Furthermore, this research demonstrates the influence of the MBT as an upper-limb power marker in older adults.