Progenitor-intrinsic Metabolic Sensing Promotes Hematopoietic Homeostasis

Hematopoietic homeostasis is maintained by stem and progenitor cells in part by extrinsic feedback cues triggered by mature cell loss. We demonstrate a different mechanism by which hematopoietic progenitors intrinsically anticipate and prevent the loss of mature progeny through metabolic switches. We examined hematopoiesis in mice conditionally deficient in long-chain fatty acid oxidation (carnitine palmitoyltransferase 2, Cpt2), glutaminolysis (glutaminase, Gls), or mitochondrial pyruvate import (mitochondrial pyruvate carrier 2, Mpc2). While genetic ablation of Cpt2 or Gls minimally impacted most blood lineages, deletion of Mpc2 led to a sharp decline in mature myeloid cells. However, MPC2-deficient myeloid cells rapidly recovered due to a transient increase in myeloid progenitor proliferation. Competitive bone marrow chimera and stable isotope tracing experiments demonstrated that this proliferative burst was intrinsic to MPC2-deficient progenitors and accompanied by a metabolic switch to glutaminolysis. Thus, hematopoietic progenitors intrinsically adjust to metabolic perturbations independently of feedback from downstream mature cells to maintain homeostasis.

Effects of Different Forms of Extrinsic Feedback on the Accuracy of Force Production and to Differentiate this Force in the Simple Cyclic Movements of the Upper and Lower Limb

Background: This study aimed to assess the accuracy of force production by the limbs and to identify the ability to differentiate this force during a progressively increasing value, in response to different types of extrinsic feedback. Material and methods: The study involved nineteen healthy and physically active boys and girls aged 12.82±0.34 years, body height 157.05±9.02 cm, and body mass 44.89±7.89 kg. The tasks were to perform a series of right and left upper limb pulls and pushes with increasing force using the levers of the kinesthesiometer and a series of lower limb presses on the pedal of the kinesthesiometer. The tasks were completed in three feedback conditions: no feedback, sound feedback, verbal feedback, and the retention test was used. To assess the level of accuracy of force production, the novel index of force production accuracy (FPAIndex) was used. Results: The outcomes expressing the value of FPAIndex on the point scale indicated that the highest level of kinesthetic differentiation was observed when no feedback was provided (1.17 points), and the lowest kinesthetic differentiation was recorded when verbal feedback was provided (3.33 points). However, they were devoid of statistical value. The repeated-measures analysis of variance ANOVA with the Tukey post-hoc test (HSD) indicated a significant lowest (p=0.0402) level of accuracy of FPA (x̄ 36.12±18.29 [N]) only for the act of left lower limb press (LL PRESS) in the retention test, while no feedback was provided to the subjects. Conclusions: The results of this study showed that verbal and sound extrinsic feedback did not affect the accuracy of force production by the upper and lower limbs and the ability to differentiate this force in simple movements among children.

The Effect of Feedback on Manual Therapy Skill Acquisition: A Systematic Review

Objective To investigate the influences of feedback on manual therapy skill acquisition as presented in the literature. Data Source(s) An electronic search was conducted across 4 databases: PubMed, EBSCOhost, SPORTDiscus, and CINAHL. The key words that were used in the search included manual therapy, physiotherapy, mobilizations, manipulation, education, instruction, feedback, intrinsic feedback, and extrinsic feedback. The Boolean phrases AND and OR were used to combine the search terms. Study Selections Studies that collected outcomes related to manual therapy skill acquisition from inception of the databases to September 2019 were included. Studies were excluded if they examined solely patient-rated or clinical outcomes of manual therapy or did not use feedback as the primary instructional intervention. Data Synthesis After quality appraisal with the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies, the articles included in the review were categorized according to generalized manual therapy skills. Joint distraction/traction was the skill examined in 2 studies. The effect of feedback on joint mobilizations was investigated in 5 studies. Studies examining joint manipulations represented the largest portion of the articles in this review, with 11 total studies being included. The primary forms of feedback that were examined in the literature included visual, verbal, and combined forms of auditory and visual feedback. Conclusion(s) Visual feedback that provides learners with graphical representations of their performance, such as force-time relationships, appear to have the greatest effects in improving force-related parameters. Visual feedback can be useful during the initial acquisition phases of manual therapy skills, as indicated by the concentration of significant findings immediately after use in training sessions. A limited number of studies examining outcomes at long-term follow-up reported that training effects decrease rapidly over time. Thus, future studies should investigate if optimal dosages or scheduling strategies exist to increase the retention of effects.

Speed of Processing and Personality: The Influence of Personality and Extrinsic Feedback on the Performance of Cognitive Tasks

Background: Feedback is considered as an effective means of motivating, guiding, and reinforcing desired behaviours. However, the ways to interpret external feedback may be different among individuals with different personality traits; therefore, this would influence the effects of feedback on performance. Accordingly, the influencing effects of personality towards different styles of feedback on cognitive task performance were examined. Methods: Participants (N = 71) were given three Stroop tasks as a dependent variable, whereas the Trail Making Task was an independent variable; additionally, a personality test was used to record the personality traits of each participant. The relationship between personality and feedback-induced changes in Stroop performance was computed by means of Pearson correlation, followed by a mixed-effect model to demonstrate the effect of personality on the overall performance with feedback. Results: The statistical analysis indicated that performance from those with higher levels of extraversion generally profitted from feedback, irrespective of whether it was negative feedback (r = 0.201) or positive feedback (r = 0.205). Additionally, the moderating effect of personality on feedback and performance was demonstrated. Conclusions: The limitations of the sample size and other external influences may have reduced the representativeness of the research. Nonetheless, more potential influencing factors need to be included and explored in future research.

FEEDBACK AND SPORT PERFORMANCE: STUDY AT PPLD ATHLETES IN EAST NUSA TENGGARA PROVINCE

This study reports the implementation feedback on sport performance of athlete at the PPLD East NusaTenggara (ENT) Province. This study used a qualitative approach with type of phenomenology. The research subjects were two athletes who had have international achievements which determined by using purpose sampling technique. The data was collected by participation observation, interview, and documentation. The result of the study found that the extrinsic feedback is still dominates in improving sport performance of PPLD athletes. Coaches and athletes used verbal and non-verbal feedback which are positive, affirmative, and constructive this enhancing self-esteem, self-confidence, and self-efficacy of the athletes. Moreover, with the feedback make the athlete more eager and diligent in practice to improve their sport performance.