Corrigendum: Are Family Physical Activity Habits Passed on to Their Children?

[This corrects the article DOI: 10.3389/fpsyg.2021.741735.].

Sensitivity of the novel two-point force-velocity model: an assessment of leg muscle mechanical capacities.

The recently proposed two-point force-velocity (F-V) model requires further evaluation in order to develop into a simple tool for muscle mechanical capacities assessment. Therefore, the first aim of this study was to assess the concurrent validity of the proposed model. The second aim of this study was to assess the sensitivity of the proposed model concerning participants of different levels of physical fitness when performing different dynamic tasks. Female elite volleyball players (N = 10; age 22 ± 2 years) and female physical education students (N = 10; age 22 ± 2 years) were tested on maximum countermovement jumps (CMJ) and 6 s maximal cycling sprint (MCS), where manipulation of loads provided a range of F and V data. The assessed F-V relationships were valid in comparison with the standard model. Moreover, the concurrent validity of the maximum force parameter (F0) was high for MCS (r ≥ 0.89) and moderate to low for CMJ (r = 0.43). Sensitivity analysis revealed significant differences between F0 in both leg tests (p < 0.04), along with maximum power parameter in CMJ (p = 0.034) between the groups. The proposed model could provide sport practitioners with a straightforward and very effective tool for assessing muscle mechanical capacities.

Are Family Physical Activity Habits Passed on to Their Children?

Studies of the familial association of physical activity (PA) and sedentary behavior (SB) have increased in recent years. However, there is a lack of studies that have objectively examined the correlates between parents, grandparents, and childrens' PA. Therefore, the purpose of this study was to measure PA using accelerometers to determine the extent to which PA and SB correlate among parents, grandparents, and children. A sample of 169 children between 11-14 years (77 boys and 97 girls), 225 parents (98 males and 127 females) and 52 grandparents (16 males and 36 females) were recruited for the current study. Accelerometers RM42 (UKK Terveyspalvelut Oy, Tampere, Finland) were used to determine PA levels of children, parents and grandparents. Epoch was set to 1 s. Mothers' moderate-to-vigorous PA (MVPA) was associated with children's MVPA (p < 0.05). After adjusting for age, BMI (child), and educational status, the results remain the same. Results of linear regression analyses for boys' sedentary time showed that fathers' sedentary time was significantly associated with boys (p < 0.01), but not with girls. The association of grandmothers' and grandfathers' MVPA activity with that of children showed that grandparents' MVPA, when adjusted for age, BMI, and educational status, was not a significant predictor (p > 0.05) of children's MVPA (total sample). In contrast, grandfathers' sedentary behavior was a significant predictor (ß = 0.269; p < 0.05) of children's sedentary behavior (total sample). The results of the current study suggest that parental involvement in PA, particularly by mothers, is important for children's PA and, accordingly, healthy outcomes.

Associations of mode and distance of commuting to school with cardiorespiratory fitness in Slovenian schoolchildren: a nationwide cross-sectional study.

BACKGROUND: It is unclear whether active commuting has the potential to improve children's health. This study examined the association of commuting mode and distance with children's cardiorespiratory fitness (CRF). METHODS: We conducted a cross-sectional study, including 713 Slovenian schoolchildren aged 12 to 15 years. Commuting modes were self-reported, and four commuting groups were constructed, while CRF was determined with a 20-m shuttle run test. The distance from home to school was calculated using the Geographic Information System. Effects of commuting mode and distance, controlling for age, gender and amount of total physical activity, were evaluated using general two linear models (one for each direction of commuting to/from school). RESULTS: The main effect of commuting group on CRF and its interaction with distance were significant in the direction from school to home (P = 0.013 and P = 0.028, respectively), but not in the opposite direction. Predicted differences in CRF between commuting groups were moderate and generally higher in males than in females. When comparing commuting group median distance from home to school, males driven by car had around 4 ml/min/kg lower predicted CRF than those who walked (P = 0.01) or used wheels commuting (e.g., bicycle, skateboard). CONCLUSIONS: The distance of commuting had a small effect on CRF, except in the Car group where children who live close to school had significantly lower CRF than those living further away. Children driven by car who live within wheels or walk distance from school should be targeted by interventions promoting active transport.

Effect of Different Types of Loads on the Force-Velocity Relationship Obtained During the Bench Press Throw Exercise.

ABSTRACT: Cosic, M, Knezevic, OM, Nedeljkovic, A, Djuric, S, Zivkovic, MZ, and Garcia-Ramos, A. Effect of different types of loads on the force-velocity relationship obtained during the bench press throw exercise. J Strength Cond Res 35(9): 2401-2406, 2021-This study aimed (a) to evaluate the degree of linearity of the force-velocity (F-V) relationship across different types of loads, (b) to compare the magnitude of the F-V relationship parameters (maximum values of force [F0], velocity [V0], and power [Pmax]) between the different types of loads, and (c) to explore the concurrent validity of F0 with traditional measures of maximal strength. The F-V relationships of 15 physically active men (age: 20.9 ± 2.0 years, bench press 1 repetition maximum relative to body mass: 1.20 ± 0.10 kg·kg-1) were determined during the bench press throw exercise using predominantly gravitational (W), inertial (I), and combined (W + I) loads. The bench press maximal isometric force (Fiso) and the 1RM were also assessed. The individual F-V relationships were highly linear regardless of the type of load considered (median r [range] = 0.98 [0.94, 1.00]). The W + I load provided the largest value of F0 (972 ± 45 N; 6.0 and 14.6% higher than W and I, respectively), the I load the largest value of V0 (2.99 ± 0.34 m·s-1; 40.4 and 20.1% higher than W and W + I, respectively), and the W load the lowest value of Pmax (501 ± 46 W; -22.7 and -17.1% lower than I and W + I, respectively). The F0 obtained from the W load presented the highest association with Fiso and 1RM values (r > 0.90). The W + I load and the I load should be recommended to work closer to the F0 and V0 capacities, respectively. However, the W load should be recommended to assess maximal strength capacity through the value of F0.

The assessment of muscle mechanical properties in multi-joint movements reveals inverse correlation of leg muscle force and power with gait transition speed.

BACKGROUND: The impact that mechanical factors might have on gait reorganization was evaluated by the relationship between muscle mechanical capacity of isolated leg muscle groups and transition speed in previous studies. However, until now there are no studies that explored the relationship between muscle mechanical properties measured in cyclic multi-joint movements and gait transition speed. RESEARCH QUESTION: What is the nature of the relationship between gait transition speed and muscle mechanical capacities measured in cyclic multi-joint movements? METHODS: The sample included 18 physically active male adults, stratified by anthropometric dimensions. Individual walk-to-run (WRT) and run-to-walk transition speed (RWT) were determined using the standard incremental protocol. Mechanical capacities of leg muscles were assessed by linear force-velocity models obtained during treadmill locomotion and on bicycle-ergometer. RESULTS: The results revealed inverse correlation between WRT and RWT and maximal force assessed on treadmill (F0; r = -0.57 and r = -0.54, respectively), as well with F0 (r = -0.65 and r = -0.58, respectively) and maximal power (Pmax; -0.66 and -0.65, respectively) collected on bicycle-ergometer. SIGNIFICANCE: This study confirmed that mechanical muscle capacities are important physical limitation factors of transition speed, explaining over 36 % of the variance. The findings showed that a novel approach, with high biomechanical similarities with natural locomotion, revealed different results (negative correlations) in comparison to previous studies.

Is Test Standardization Important when Arm and Leg Muscle Mechanical Properties are Assessed through the Force-Velocity Relationship?

The force-velocity (F-V) relationship observed in multi-joint tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F-V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F-V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F-V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F-V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F-V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = -0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F-V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F-V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.

Assessment of the two-point method applied in field conditions for routine testing of muscle mechanical capacities in a leg cycle ergometer.

PURPOSE: The aim of this study was to compare the reliability and magnitude of the force-velocity (F-V) relationship parameters [maximum force (F0), maximum velocity (V0), F-V slope, and maximum power (P0)] obtained through the application of only two loads (i.e., two-point method) vs. six loads (i.e., multiple-point method). METHODS: Ten physically active men (age 19.5 ± 0.9 years, body mass 79.0 ± 9.0 kg, height 183.9 ± 8.4 cm) conducted four testing sessions after a preliminary familiarization session with the leg cycle ergometer exercise. In a counterbalanced order, subjects performed two sessions of the multiple-point method (six loads applied for the F-V modeling) over 1 week and two sessions of the two-point method (only the lightest and heaviest loads were applied) over another week. RESULTS: The main findings revealed that (I) the reliability of the F-V relationship parameters was very high and generally of comparable magnitude for both the multiple- [coefficient of variation (CV) range 1.91-3.94%; intraclass correlation coefficient (ICC) range 0.72-0.99] and two-point methods [CV range 1.41-4.62%; ICC range 0.76-0.95], (II) the magnitude of the same parameters obtained from both methods was highly correlated (r > 0.80), and (III) the P0 assessed from the multiple-point method was significantly lower than the obtained from the two-point method [P = 0.041; effect size (ES) 0.36] due to a significant decrease in F0 (P = 0.039; ES 0.41) with no significant differences observed for V0 (P = 0.570; ES - 0.15). CONCLUSIONS: These results support the two-point method as a reliable, valid, and fatigue-free procedure of assessing the muscle mechanical capacities through the F-V relationship.

A Novel Two-Velocity Method for Elaborate Isokinetic Testing of Knee Extensors.

Single outcomes of standard isokinetic dynamometry tests do not discern between various muscle mechanical capacities. In this study, we aimed to (1) evaluate the shape and strength of the force-velocity relationship of knee extensors, as observed in isokinetic tests conducted at a wide range of angular velocities, and (2) explore the concurrent validity of a simple 2-velocity method. Thirteen physically active females were tested for both the peak and averaged knee extensor concentric force exerted at the angular velocities of 30°-240°/s recorded in the 90°-170° range of knee extension. The results revealed strong (0.960

Force-velocity relationship of leg muscles assessed with motorized treadmill tests: Two-velocity method.

Linear regression models applied on force (F) and velocity (V) data obtained from loaded multi-joint functional movement tasks have often been used to assess mechanical capacities of the tested muscles. The present study aimed to explore the properties of the F-V relationship of leg muscles exerting the maximum pulling F at a wide range of V on a standard motorized treadmill. Young and physically active male and female subjects (N=13+15) were tested on their maximum pulling F exerted horizontally while walking or running on a treadmill set to 8 different velocities (1.4-3.3m/s). Both the individual (median R=0.935) and averaged across the subjects F-V relationships (R=0.994) proved to be approximately linear and exceptionally strong, while their parameters depicting the leg muscle capacities for producing maximum F, V, and power (P; proportional to the product of F and V) were highly reliable (0.84

Muscle Force-Velocity Relationships Observed in Four Different Functional Tests.

The aims of the present study were to investigate the shape and strength of the force-velocity relationships observed in different functional movement tests and explore the parameters depicting force, velocity and power producing capacities of the tested muscles. Twelve subjects were tested on maximum performance in vertical jumps, cycling, bench press throws, and bench pulls performed against different loads. Thereafter, both the averaged and maximum force and velocity variables recorded from individual trials were used for force-velocity relationship modeling. The observed individual force-velocity relationships were exceptionally strong (median correlation coefficients ranged from r = 0.930 to r = 0.995) and approximately linear independently of the test and variable type. Most of the relationship parameters observed from the averaged and maximum force and velocity variable types were strongly related in all tests (r = 0.789-0.991), except for those in vertical jumps (r = 0.485-0.930). However, the generalizability of the force-velocity relationship parameters depicting maximum force, velocity and power of the tested muscles across different tests was inconsistent and on average moderate. We concluded that the linear force-velocity relationship model based on either maximum or averaged force-velocity data could provide the outcomes depicting force, velocity and power generating capacity of the tested muscles, although such outcomes can only be partially generalized across different muscles.

A simple method for assessment of muscle force, velocity, and power producing capacities from functional movement tasks.

A range of force (F) and velocity (V) data obtained from functional movement tasks (e.g., running, jumping, throwing, lifting, cycling) performed under variety of external loads have typically revealed strong and approximately linear F-V relationships. The regression model parameters reveal the maximum F (F-intercept), V (V-intercept), and power (P) producing capacities of the tested muscles. The aim of the present study was to evaluate the level of agreement between the routinely used "multiple-load model" and a simple "two-load model" based on direct assessment of the F-V relationship from only 2 external loads applied. Twelve participants were tested on the maximum performance vertical jumps, cycling, bench press throws, and bench pull performed against a variety of different loads. All 4 tested tasks revealed both exceptionally strong relationships between the parameters of the 2 models (median R = 0.98) and a lack of meaningful differences between their magnitudes (fixed bias below 3.4%). Therefore, addition of another load to the standard tests of various functional tasks typically conducted under a single set of mechanical conditions could allow for the assessment of the muscle mechanical properties such as the muscle F, V, and P producing capacities.

Selective Effects of Training Against Weight and Inertia on Muscle Mechanical Properties.

PURPOSE: To explore the effects of training against mechanically different types of loads on muscle force (F), velocity (V), and power (P) outputs. METHODS: Subjects practiced maximum bench throws over 8 wk against a bar predominantly loaded by approximately constant external force (weight), weight plates (weight plus inertia), or weight plates whose weight was compensated by a constant external force pulling upward (inertia). Instead of a typically applied single trial performed against a selected load, the pretest and posttest consisted of the same task performed against 8 different loads ranging from 30% to 79% of the subject's maximum strength applied by adding weight plates to the bar. That provided a range of F and V data for subsequent modeling by linear F-V regression revealing the maximum F (F-intercept), V (V-intercept), and P (P = FV/4). RESULTS: Although all 3 training conditions resulted in increased P, the inertia type of the training load could be somewhat more effective than weight. An even more important finding was that the P increase could be almost exclusively based on a gain in F, V, or both when weight, inertia, or weight-plus-inertia training load were applied, respectively. CONCLUSIONS: The inertia training load is more effective than weight in increasing P and weight and inertia may be applied for selective gains in F and V, respectively, whereas the linear F-V model obtained from loaded trials could be used for discerning among muscle F, V, and P.

Evaluation of force-velocity and power-velocity relationship of arm muscles.

PURPOSE: A number of recent studies have revealed an approximately linear force-velocity (F-V) and, consequently, a parabolic power-velocity (P-V) relationship of multi-joint tasks. However, the measurement characteristics of their parameters have been neglected, particularly those regarding arm muscles, which could be a problem for using the linear F-V model in both research and routine testing. Therefore, the aims of the present study were to evaluate the strength, shape, reliability, and concurrent validity of the F-V relationship of arm muscles. METHODS: Twelve healthy participants performed maximum bench press throws against loads ranging from 20 to 70 % of their maximum strength, and linear regression model was applied on the obtained range of F and V data. One-repetition maximum bench press and medicine ball throw tests were also conducted. RESULTS: The observed individual F-V relationships were exceptionally strong (r = 0.96-0.99; all P < 0.05) and fairly linear, although it remains unresolved whether a polynomial fit could provide even stronger relationships. The reliability of parameters obtained from the linear F-V regressions proved to be mainly high (ICC > 0.80), while their concurrent validity regarding directly measured F, P, and V ranged from high (for maximum F) to medium-to-low (for maximum P and V). CONCLUSIONS: The findings add to the evidence that the linear F-V and, consequently, parabolic P-V models could be used to study the mechanical properties of muscular systems, as well as to design a relatively simple, reliable, and ecologically valid routine test of the muscle ability of force, power, and velocity production.