Search Results

Drawing upon the nonlinear model of attention focus, the purpose of this study was to compare the intrinsic and intentional dynamics of task-related thoughts (TRT) in trained runners and nonrunners during an incremental maximal test. Fourteen trained runners and 14 nonrunners were assigned to 2 conditions: intrinsic (nonimposed thoughts) and intentional (imposed, task-unrelated thoughts; TUT). A significant effect of running velocity over TUT/TRT dynamics in both groups and conditions was observed (p < .001). Although, all participants received instructions to keep TUT for the entire duration of the test, an initially stable TUT phase was followed by a metastable phase (i.e., switches between TUT and TRT) an a final stable TRT phase nearing volitional exhaustion. The stable TRT phase lasted longer in runners group (p < .05) and included higher probabilities in pace monitoring thoughts subcategory (p < .05). The results revealed that trained runners seem to use TRT (i.e., pace monitoring) to maximize performance, and confirm the nonlinear model of attention focus during incremental maximal run in trained runners and nonrunners.

Context: Blood flow restriction (BFR) increases muscle size and strength when combined with low loads, but various methods are used to produce this stimulus. It is unclear how using elastic knee wraps can impact acute muscular responses compared with using nylon cuffs, where the pressure can be standardized. Objective: Investigate how elastic knee wraps compare with nylon cuffs and high-load (HL)/low-load (LL) resistance exercise. Design: A randomized cross-over experimental design using 6 conditions combined with unilateral knee extension. Setting: Human Performance Laboratory. Participants: A total of 9 healthy participants (males = 7 and females = 2) and had an average age of 22 (4) years. Intervention: LL (30% of 1-repetition maximum [1-RM]), HL (70% 1-RM), BFR at 40% of arterial occlusion pressure (BFR-LOW), BFR at 80% of arterial occlusion pressure (BFR-HIGH), elastic knee wraps stretched by 2 in (PRACTICAL-LOW), and elastic knee wraps stretched to a new length equivalent to 85% of thigh circumference (PRACTICAL-HIGH). BFR and practical conditions used 30% 1-RM. Main Outcome Measures: Muscle thickness, maximum voluntary isometric contraction, and electromyography amplitude. Bayesian statistics evaluated differences in changes between conditions using the Bayes factor (BF₁₀), and median and 95% credible intervals were reported from the posterior distribution. Results: Total repetitions completed were greater for BFR-LOW versus PRACTICAL-HIGH (BF₁₀ = 3.2, 48.6 vs 44 repetitions) and greater for PRACTICAL-LOW versus BFR-HIGH (BF₁₀ = 717, 51.8 vs 36.3 repetitions). Greater decreases in changes in maximum voluntary isometric contraction were found in PRACTICAL-HIGH versus HL (BF₁₀ = 1035, ∼103 N) and LL (BF₁₀ = 45, ∼66 N). No differences in changes in muscle thickness were found between LL versus PRACTICAL-LOW/PRACTICAL-HIGH conditions (BF₁₀ = 0.32). Greater changes in electromyography amplitude were also found for BFR-LOW versus PRACTICAL-HIGH condition (BF₁₀ = 6.13, ∼12%), but no differences were noted between the other BFR conditions. Conclusions: Overall, elastic knee wraps produce a more fatiguing stimulus than LL or HL conditions and might be used as an alternative to pneumatic cuffs that are traditionally used for BFR exercise.

Background : Half-marathon races have become increasingly more popular with many recreational athletes all around the world. New and recreational runners are likely to have the greatest need for training advice to set running paces during long-distance races. Purpose: To develop a simple equation to estimate half-marathon time from the Cooper test and verify its validity. Methods: One hundred ninety-eight recreational runners (177 men and 21 women, 40 [6.8] years and 33.7 [8] years, respectively) participated in this study. All runners completed the Cooper test 7 to 10 days prior to races. A stepwise multiple regression analysis was performed to select the main predictors of half-marathon time. Results: Simple correlation analysis showed that Cooper test performance (distance) was a good construct to estimate half-marathon time (r = −.906; 95% confidence interval, −0.927 to −0.877; P < .0001). The authors also derived an equation with a high predictive validity (R ² = .82; standard error of estimation = 5.19 min) and low systematic bias (mean differences between the predicted value and the criterion of 0.48 [5.2] min). Finally, the concordance coefficient of correlation (.9038) and proportional bias analysis (Kendall τ = −.0799; 95% confidence interval, −0.184 to 0.00453; P = .09) confirmed a good concurrent validity. Conclusion: In this study, the authors derived an equation from the Cooper test data with a high predictive and concurrent validity and low bias.

The multiple process model contends that there are two forms of online control for manual aiming: impulse regulation and limb-target control. This study examined the impact of visual information processing for limb-target control. We amalgamated the Gunslinger protocol (i.e., faster movements following a reaction to an external trigger compared with the spontaneous initiation of movement) and Müller-Lyer target configurations into the same aiming protocol. The results showed the Gunslinger effect was isolated at the early portions of the movement (peak acceleration and peak velocity). Reacted aims reached a longer displacement at peak deceleration, but no differences for movement termination. The target configurations manifested terminal biases consistent with the illusion. We suggest the visual information processing demands imposed by reacted aims can be adapted by integrating early feedforward information for limb-target control.

Background: School physical education (PE) is one of the most effective public health tools to increase youth physical activity, yet compliance with PE mandates is low. In an effort to ensure adherence to state PE law, a 2013 lawsuit was filed against 37 California school districts that were found to be noncompliant. This study sought to assess school personnel’s perceptions of the lawsuit’s impact on PE mandate compliance, understand barriers and facilitators to lawsuit compliance, and identify potential unintended consequences of the lawsuit. Methods: Phone interviews (n = 97) were conducted with personnel in districts/schools that were parties to the lawsuit and in matched control districts/schools that were not parties to the lawsuit. Results: Interviewees reported that PE minutes increased in schools that were parties to the lawsuit, primarily due to settlement requirements mandating PE tracking and reporting, thereby increasing accountability for PE. Time lost on paperwork was the most often cited barrier to compliance. Unwillingness to participate in PE-related research for fear of incrimination was the primary unintended consequence. Conclusions: When existing PE minute laws are not implemented or enforced, greater accountability is needed. In this case, litigation appears to be an effective accountability mechanism to increase compliance with law.

The main aim of this study was to analyze the effect of resistance training programs differing in set configuration on mechanical force-velocity profiles. Thirteen participants performed 10 unilateral knee extension training sessions over 5 weeks. Each limb was randomized to one of the following set configurations: traditional (4 sets of 8 repetitions at maximum intended velocity, 10RM load, 3-min pause between sets) or interrepetition rest (32 maximum intended velocity repetitions, 10RM load, 17.4 s of rest between each repetition). Velocity of each repetition was recorded throughout the program. Before and after training, individual linear force velocities were calculated, and the following parameters were obtained: force and velocity axis intercept, slope, and estimated maximum power. Mean velocity was higher throughout the program for interrepetition rest configuration (0.54 ± 0.01 vs. 0.48 ± 0.01 m∙s⁻¹ for interrepetition rest, and traditional configuration respectively; main effect of set configuration: P < .001). There was a significant increase in force and velocity intercepts, but a steeper negative slope after both training protocols (main effect of time: P < .001 for every variable). Differences in resistance training velocity did not affect the adaptations. Our results suggest that, in a short-term program, maximum intended rather than actual velocity is a key factor to modulate strength adaptations.