Continuous Jumps Enhance Twitch Peak Torque and Sprint Performance in Highly Trained Sprint Athletes

2020 ◽  
pp. 1-8
Author(s):  
Haiko B. Zimmermann ◽  
Débora Knihs ◽  
Fernando Diefenthaeler ◽  
Brian MacIntosh ◽  
Juliano Dal Pupo
Keyword(s):  
Time Course ◽  
Mixed Model ◽  
Performance Enhancement ◽  
Peak Torque ◽  
Sprint Performance ◽  
Postactivation Potentiation ◽  
Warm Up ◽  
Mixed Model Analysis ◽  
Post Hoc ◽  
Vertical Jumps

Purpose: The objective of this study was to analyze the effects of a conditioning activity (CA) composed of continuous countermovement jumps on twitch torque production and 30-m sprint times. Methods: A total of 12 sprint athletes, 10 men (23.5 [7.7] y) and 2 women (23.0 [2.8] y), volunteered to participate in this study. The participants were evaluated in 2 sessions as follows: (1) to determine the effects of the CA (3 sets of 5 continuous vertical jumps with a 1-min interval between sets) on 30-m sprint performance over time (2, 4, 6, 8, and 10 min) and (2) to evaluate twitch peak torque to determine the magnitude and time course of the induced postactivation potentiation at the same recovery intervals. Results: Mixed-model analysis of variance with Bonferroni post hoc verified that there was a decrease on the 30-m sprint time at 2 minutes (P = .01; Δ = 2.78%; effect size [ES] = 0.43) and 4 minutes (P = .02; Δ = 2%, ES = 0.30) compared with pre when the CA preceded the sprints. The peak torque of quadriceps also showed significant increase from pretest to 2 minutes (P < .01; Δ = 17.0% [12.2%]; ES = 0.45) and 4 minutes (P = .02; Δ = 7.2% [8.8%]; ES = 0.20). Conclusion: The inclusion of CA composed of continuous countermovement jumps in the warm-up routine improved 30-m sprint performance at 2- and 4-minute time intervals after the CA (postactivation performance enhancement). Since postactivation potentiation was confirmed with electrical stimulation at the time when sprint performance increased, it was concluded that postactivation potentiation may have contributed to the observed performance increases.

scholarly journals Rate and Determinants of Excessive Fat-Free Mass Loss After Bariatric Surgery

2020 ◽  
Vol 30 (8) ◽  
pp. 3119-3126
Author(s):  
Malou A. H. Nuijten ◽  
Valerie M. Monpellier ◽  
Thijs M. H. Eijsvogels ◽  
Ignace M. C. Janssen ◽  
Eric J. Hazebroek ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Time Course ◽  
Mixed Model ◽  
Linear Regression Analysis ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Fat Free Mass ◽  
Mixed Model Analysis ◽  
Post Surgery ◽  
Post Bariatric Surgery

Abstract Purpose Fat-free mass (FFM) loss is a concerning aspect of bariatric surgery, but little is known about its time-course and factors related with excessive FFM loss. This study examined (i) the progress of FFM loss up to 3 years post-bariatric surgery and (ii) the prevalence and determinants of excessive FFM loss. Materials and Methods A total of 3596 patients (20% males, 43.5 ± 11.1 years old, BMI = 44.2 ± 5.5 kg/m2) underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) surgery. Bioelectrical impedance analysis was performed preoperatively and 3, 6, 9, 12, 18, 24 and 36 months post-surgery. Changes in body composition were assessed by mixed model analysis. Prevalence of excessive FFM loss (based on three different cutoff values: ≥ 25%, ≥ 30% and ≥ 35% FFM loss/weight loss (= %FFML/WL)) was estimated and its determinants were assessed by linear regression analysis. Results Highest rates of FFM loss were found at 3 and 6 months post-surgery, reflecting 57% and 73% of peak FFM loss, respectively. Prevalence of excessive FFM loss ranged from 14 to 46% at 36 months post-surgery, with an older age (β = 0.14, 95%CI = 0.10–0.18, P < .001), being male (β = 3.99, 95%CI = 2.86–5.12, P < .001), higher BMI (β = 0.13, 95%CI = 0.05–0.20, P = .002) and SG (β = 2.56, 95%CI = 1.36–3.76, P < .001) as determinants for a greater %FFML/WL. Conclusion Patients lost most FFM within 3 to 6 months post-surgery. Prevalence of excessive FFM loss was high, emphasizing the need for more vigorous approaches to counteract FFM loss. Furthermore, future studies should assess habitual physical activity and dietary intake shortly after surgery in relation to FFM loss.

scholarly journals Which Test of Divergent Thinking Is Best?

2016 ◽  
Vol 3 (1) ◽  
pp. 4-18 ◽  
Author(s):  
Mark A. Runco ◽  
Ahmed M. Abdulla ◽  
Sue Hyeon Paek ◽  
Fatima A. Al-Jasim ◽  
Hanadi N. Alsuwaidi
Keyword(s):  
Divergent Thinking ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Mixed Model Analysis ◽  
Demographic Questionnaire ◽  
Problem Generation ◽  
Behavior Scale ◽  
Realistic Problem ◽  
Post Hoc ◽  
Better Than

AbstractDivergent thinking (DT) tests are probably the most commonly used measures of creative potential. Several extensive batteries are available but most research relies on one or two specific tests rather than a complete battery. This may limit generalizations because tests of DT are not equivalent. They are not always highly inter-correlated. Additionally, some DT tests appear to be better than others at eliciting originality. This is critical because originality is vital for creativity. The primary purpose of the present study was to determine which test of DT elicits the most originality. Seven measures of DTwere administered on a sample of 611 participants in eight Arabic countries. The tests were Figural, Titles, Realistic Presented Problems, Realistic Problem Generation, Instances, Uses, and Similarities. The Quick Test of Convergent Thinking, Runco’s Ideational Behavior Scale, and a demographic questionnaire were also administered. A linear mixed model analysis confirmed that the originality scores in the DT tests differed by test. Post-hoc tests indicated that the Titles and Realistic Problem Generation tests produced the highest mean originality scores, whereas the Realistic Presented Problems test produced the lowest mean originality scores. These differences confirm that research using only one DT test will not provide generalizable results.

Appetite-stimulating effect of gabapentin vs mirtazapine in healthy cats post-ovariectomy

2020 ◽  
Vol 22 (12) ◽  
pp. 1176-1183
Author(s):  
Marco Fantinati ◽  
Julien Trnka ◽  
Amélia Signor ◽  
Séverine Dumond ◽  
Géraldine Jourdan ◽  
...  
Keyword(s):  
Placebo Group ◽  
Food Intake ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Repeated Measure ◽  
Mixed Model Analysis ◽  
Treatment Groups ◽  
Significant Difference ◽  
Post Hoc ◽  
Difference Test

Objectives The aim of the study was to evaluate the appetite-stimulating effect of gabapentin by comparing it with mirtazapine in healthy cats in the first 8 h after ovariectomy surgery. Methods This double-masked, placebo-controlled, prospective clinical trial included 60 healthy cats presented to the hospital for ovariectomy: 20 received gabapentin, 21 received mirtazapine and 19 received a placebo immediately before and 6 h after surgery. Food was offered at 2, 4, 6 and 8 h post-ovariectomy. After each meal, food intake was measured. Data were analysed using repeated-measure ANOVA and a linear mixed-model analysis. Post-hoc Tukey’s honest significant difference test was performed for multiple comparisons. Results Food intake increased in both treatment groups vs placebo. No statistically significant difference was found between cats treated with gabapentin or mirtazapine. Conclusions and relevance Cats receiving gabapentin ate more than cats in the placebo group. Thirty percent of cats in the gabapentin group covered their resting energy requirements, while none of the cats in the placebo group did. Gabapentin and mirtazapine produced similar effects on food intake.

scholarly journals Neuroanatomical Alterations in Patients With Tinnitus Before and After Sound Therapy: A Combined VBM and SCN Study

2020 ◽  
Author(s):  
Xuan Wei ◽  
Han Lv ◽  
Qian Chen ◽  
Zhaodi Wang ◽  
Chunli Liu ◽  
...  
Keyword(s):  
Mixed Model ◽  
Pulse Sequence ◽  
Therapy Group ◽  
Image Data ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Mixed Model Analysis ◽  
Sound Therapy ◽  
Before And After ◽  
Post Hoc

Abstract Background: Many neuroanatomical alterations have been detected in patients with tinnitus in previous studies. However, little is known about morphological and structural covariance network (SCN) changes before and after long-term sound therapy. This study aimed to explore alterations in brain anatomical and SCN changes in patients with idiopathic tinnitus using voxel-based morphometry (VBM) analysis 24 weeks before and after sound therapy. Methods: Thirty-three tinnitus patients underwent magnetic resonance imaging scans at baseline and after 24 weeks of sound therapy. Twenty-six age- and sex-matched healthy control (HC) individuals also underwent two scans over a 24-week interval; 3.0T MRI and high-resolution 3D structural images were acquired with a 3D-BRAVO pulse sequence. Structural image data preprocessing was performed using the VBM8 toolbox. The Tinnitus Handicap Inventory (THI) score was acquired in the tinnitus group to assess the severity of tinnitus and tinnitus-related distress. Two-way mixed model analysis of variance (ANOVA) and post hoc analyses were performed to determine differences between the two groups (patients and HCs) and between the two scans (at baseline and at the 24th week). Two-sample t tests, paired-samples t tests, and Pearson’s correlation analysis were used in the post hoc analysis.Results: Interaction effects between the two groups and the two scans demonstrated significantly different gray matter (GM) volume in the right parahippocampus gyrus, right caudate, left superior temporal gyrus, left cuneus gyrus and right calcarine gyrus; we found significantly decreased GM volume in the above five brain regions among the tinnitus patients before sound therapy (baseline) compared to that in the HC group. The 24-week sound therapy group demonstrated significantly greater brain volume compared with the baseline group among these brain regions. We did not find significant differences in brain regions between the 24-week sound therapy and HC groups. The SCN results showed that the left superior temporal gyrus and left rolandic operculum were significantly different in nodal efficiency, nodal degree centrality and nodal betweenness centrality after FDR correction. Decreased THI scores and GM volume changes between the left thalamus and right thalamus were not correlated. Conclusions: This study characterized the effect of sound therapy on brain GM volume, especially in the left superior temporal lobe. Notably, sound therapy had a normalizing effect on tinnitus patients.

scholarly journals The effects of a postactivation potentiation warm-up on subsequent sprint performance

2014 ◽  
Vol 15 (1) ◽  
Author(s):  
Chad E. Smith ◽  
James C. Hannon ◽  
Brian McGladrey ◽  
Barry Shultz ◽  
Patricia Eisenman ◽  
...  
Keyword(s):  
Sprint Performance ◽  
Kinematics Analysis ◽  
Postactivation Potentiation ◽  
Power Performance ◽  
Strength And Conditioning ◽  
Warm Up ◽  
Mixed Anova ◽  
Time Interaction ◽  
Significant Difference ◽  
Main Effect

AbstractPurpose. Many strength and conditioning professionals propose that postactivation potentiation (PAP) warm-ups enhance power performance although there are few studies conducted in this regard on sprinting. Therefore, the purpose of this study was to determine the effects of a PAP warm-up on sprint performance. Methods. Twenty-four men and women completed a 40-yard (yd) sprint pretest on four nonconsecutive days followed by a PAP warm-up that included a sled resistance sprint at either 0%, 10%, 20%, or 30% of their body mass and concluded with a 40-yd dash posttest. Each resistance sprint was recorded for kinematic analysis. Results. A 2 × 2 × 4 factorial mixed ANOVA revealed a statistically significant difference between sexes in 40-yd dash times (p < 0.001). A significant main effect was found in pre- and post-40-yd dash measures regardless of sex (p < 0.001). The results indicated no significant differences in the post-40-yd dash times between sled loads and the load by time interaction. The participants’ 40-yd dash times improved 1.2% on average after the 10% load. Improvements in dash time for the 0%, 20%, and 30% loads were greater than 2%. Sprint kinematics analysis demonstrated statistically significant differences between lighter and heavier loads. Conclusions. Regardless of the significant disruptions in sprint mechanics, there appears to be a potential for heavier sled resistances to affect acute improvements in 40-yd sprint performance. However, it is unclear whether heavier sleds loads may provide greater benefit than warming up with 0% resistance.

scholarly journals Grammatikken i baggrunden – opmærksomhed under læsning

2015 ◽  
Vol 47 (47) ◽  
pp. 99 ◽  
Author(s):  
Nicoline Munck Vinther ◽  
Kasper Boye ◽  
Line Burholt Kristensen
Keyword(s):  
Error Detection ◽  
Mixed Model ◽  
Experimental Studies ◽  
Future Research ◽  
Recent Theory ◽  
Exact Nature ◽  
Detection Rates ◽  
Mixed Model Analysis ◽  
Reported Study ◽  
Post Hoc

This article reports on a psycholinguistic study of two sets of linguistic mechanisms that are employed by language users to signal the intended prioritization of attention within complex messages: focus and the lexicon-grammar contrast. The study is one of the first experimental studies of the lexicon-grammar contrast which is theoretically anchored and not merely based on an intuition-based understanding of grammar. The focus of a sentence is indicated by means of focus markers, e.g. cleft constructions and focus particles. There is a general consensus, supported by experimental results, that focus is involved in the above-mentioned form of prioritization. On the other hand, the lexicon-grammar contrast has only recently been related to prioritization of attention. A recent theory of grammar (Boye and Harder 2012) suggests that grammatical elements, such as auxiliaries and articles, are low-priority items that only serve an ancillary purpose. The reported study is centered on a letter detection task with 84 Danish participants, in which structural status (lexical vs. grammatical) and focal status (focus vs. non-focus) of elements were manipulated. While the focus manipulation did not affect error detection rates, structural status (as defined by Boye and Harder 2012) did: Grammatical elements attracted less attention (generated significantly more detection errors) than their lexical counterparts. A post hoc mixed model analysis also showed a significant interaction between focal and structural status, but the robustness and exact nature of this interaction effect is a question for future research.

scholarly journals Growth of Container-grown Cork Oak Seedlings as Affected by Foliar and Soil Application of Paclobutrazol

HortScience ◽  
2005 ◽  
Vol 40 (6) ◽  
pp. 1773-1776 ◽  
Author(s):  
Marta Pardos ◽  
Rafael Calama ◽  
Gregorio Montero ◽  
José A. Pardos
Keyword(s):  
Time Course ◽  
Mixed Model ◽  
Growth Traits ◽  
Foliar Spray ◽  
Plant Size ◽  
Quercus Suber ◽  
Cork Oak ◽  
Shoot Height ◽  
Mixed Model Analysis ◽  
Soil Drench

Four concentrations of paclobutrazol (PBZ) and two application methods (foliar spray–soil drench) were tested on 3-month-old container-grown cork oak (Quercus suber L.) seedlings. Shoot height was affected by PBZ concentration and application technique. Time course of height was modelled by nonlinear mixed model analysis. Reduced shoot height was the result of shortened and fewer internodes. A 25 to 625 ppm soil drench or 625 to 15,000 ppm foliar spray controlled over vegetative growth, resulting in a reduction between 13% and 90% in plant size relative to untreated controls. Seedlings responded to soil drench at a lower PBZ concentration than for a foliar spray, but the danger of irreversible overdosing seems greater for a soil drench. Soil drench—and foliar spray to a lesser extent—also affected other shoot and root growth traits. PBZ dose decreased root volume and dry weights in a quadratic fashion with increasing dose, but decreased diameter and number of leaves linearly.

scholarly journals Neuroanatomical Alterations in Patients With Tinnitus Before and After Sound Therapy: A Combined VBM and SCN Study

2021 ◽  
Vol 14 ◽  
Author(s):  
Xuan Wei ◽  
Han Lv ◽  
Qian Chen ◽  
Zhaodi Wang ◽  
Chunli Liu ◽  
...  
Keyword(s):  
Mixed Model ◽  
Pulse Sequence ◽  
Therapy Group ◽  
Image Data ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Mixed Model Analysis ◽  
Sound Therapy ◽  
Before And After ◽  
Post Hoc

Many neuroanatomical alterations have been detected in patients with tinnitus in previous studies. However, little is known about the morphological and structural covariance network (SCN) changes before and after long-term sound therapy. This study aimed to explore alterations in brain anatomical and SCN changes in patients with idiopathic tinnitus using voxel-based morphometry (VBM) analysis 24 weeks before and after sound therapy. Thirty-three tinnitus patients underwent magnetic resonance imaging scans at baseline and after 24 weeks of sound therapy. Twenty-six age- and sex-matched healthy control (HC) individuals also underwent two scans over a 24-week interval; 3.0T MRI and high-resolution 3D structural images were acquired with a 3D-BRAVO pulse sequence. Structural image data preprocessing was performed using the VBM8 toolbox. The Tinnitus Handicap Inventory (THI) score was assessed for the severity of tinnitus before and after treatment. Two-way mixed model analysis of variance (ANOVA) and post hoc analyses were performed to determine differences between the two groups (patients and HCs) and between the two scans (at baseline and on the 24th week). Student-Newman-Keuls (SNK) tests were used in the post hoc analysis. Interaction effects between the two groups and the two scans demonstrated significantly different gray matter (GM) volume in the right parahippocampus gyrus, right caudate, left superior temporal gyrus, left cuneus gyrus, and right calcarine gyrus; we found significantly decreased GM volume in the above five brain regions among the tinnitus patients before sound therapy (baseline) compared to that in the HC group. The 24-week sound therapy group demonstrated significantly greater brain volume compared with the baseline group among these brain regions. We did not find significant differences in brain regions between the 24-week sound therapy and HC groups. The SCN results showed that the left superior temporal gyrus and left rolandic operculum were significantly different in nodal efficiency, nodal degree centrality, and nodal betweenness centrality after FDR correction. This study characterized the effect of sound therapy on brain GM volume, especially in the left superior temporal lobe. Notably, sound therapy had a normalizing effect on tinnitus patients.

AN ATTEMPT TO INDUCE POSTACTIVATION POTENTIATION TO IMPROVE KAYAK SPRINT PERFORMANCE USING AN ON-WATER KAYAK-SPECIFIC WARM UP

2020 ◽  
Vol 20 (05) ◽  
pp. 2050026
Author(s):  
SZE YING SOH ◽  
ABDUL RASHID AZIZ ◽  
MARCUS J.C. LEE
Keyword(s):  
Power Output ◽  
Latency Period ◽  
Sprint Performance ◽  
Peak Power Output ◽  
Postactivation Potentiation ◽  
Experimental Conditions ◽  
Warm Up ◽  
Resistance Exercises ◽  
The Individual ◽  
Tennis Balls

This study explores whether an on-water kayak-specific resistance exercise (KSRE) performed during the warm-up period can induce postactivation potentiation (PAP) to improve subsequent kayak-sprint performance. The KSRE involves stringing several tennis balls around the boat’s hull to induce drag while paddling. In a laboratory setting, 10 well-trained male ([Formula: see text]) and female ([Formula: see text]) kayakers performed three repetitions of the single-arm seated-row (SASR) at 91% one-repetition maximum to induce PAP and were assessed for their peak power output while performing SASR on the Keiser machine at two-minute intervals up to 16 min. Each individual’s latency period for the onset of PAP during this exercise was recorded. In separate sessions, athletes performed in random, a 30 m kayak-sprint in a swimming pool setting after either control (no pre-performance loading) or experimental (post-PAP induction via the KSRE taking into account the individual’ onset of PAP latencies period obtained in the laboratory) conditions. Criterion measures of boat velocities of the third and fourth stroke from the start and 30 m sprint times, assessed using video, were not significantly different between control and experimental conditions. The translation of increased power output elicited via PAP using land-based resistance exercises into water-based resistance exercises to improve kayak-sprint performance remains a challenge.

scholarly journals Incidence and Time Point of Sepsis Detection as Related to Different Sepsis Definitions in Severely Burned Patients and Their Accompanying Time Course of Pro-Inflammatory Biomarkers

2021 ◽  
Vol 11 (8) ◽  
pp. 701
Author(s):  
Pia Niggemann ◽  
Daniel Rittirsch ◽  
Philipp Karl Buehler ◽  
Riccardo Schweizer ◽  
Pietro Giovanoli ◽  
...  
Keyword(s):  
Time Course ◽  
Mixed Model ◽  
White Blood Cells ◽  
Total Body Surface Area ◽  
Inflammatory Biomarkers ◽  
Burn Patients ◽  
Mixed Model Analysis ◽  
Burn Center ◽  
Sepsis Definition ◽  
Time Point

Background: Diagnosis of sepsis in burn patients remains difficult for various reasons. One major problem is the definition of sepsis itself. Therefore, previous and current sepsis definitions are a matter of ongoing validation, but a well-defined consensus on which clinical and laboratory parameters to incorporate in such a definition is lacking. The aim of the present study was to compare the incidence and time-related occurrence of septic events according to different definitions as well as their accompanying time course of pro-inflammatory biomarkers. Methods: Across the first 14 days after admission, the incidence and time point of sepsis according to three different definitions (Sepsis-3, Sepsis American Burns Association [ABA] 2007, Sepsis Zurich Burn Center) were assessed on a daily basis in adult burn patients with total body surface area (TBSA) ≥15% admitted to the Zurich Burn Center between May 2015 and October 2018. In order to investigate how well daily drawn proinflammatory biomarkers (white blood cells (WBCs), C-reactive protein (CRP), procalcitonin (PCT), and novel pancreatic stone protein (PSP)) reflect the progression of sepsis depending on its type of definition, a longitudinal mixed model analysis was performed across the first 14 days for septic and non-septic patients. Additionally, the relative increase of biomarker levels 24, 48, and 72 h prior to a septic event was analyzed for each definition used. Results: In our cohort of 90 severely burned patients, Sepsis-3 identified 46 patients (51.1%) as septic, while ABA 2007 and the Zurich Burn Center definition counted 33 patients (36.7%) and 24 patients (26.6%), respectively. Sepsis-3 detected sepsis about 1 day earlier than Sepsis ABA 2007 (p < 0.001) and about 0.5 days earlier than Sepsis Zurich Burn Center (p = 0.04). The course of pro-inflammatory biomarkers was largely unaffected by the type of sepsis definition. Irrespective of the sepsis definition, PSP was the only marker to demonstrate a highly significant interaction between time and group (sepsis versus no sepsis) (p < 0.001) with a 3.3–5.5-fold increase within 72 h before the event of sepsis, whereas CRP, PCT, and WBC showed only mild undulations. Conclusions: Despite the ongoing dilemma of how to define sepsis in burn patients, a continually calculated SOFA score as used in Sepsis-3 is advantageous to early identify a patient’s detrimental progression to sepsis. Inclusion of biomarkers, such as PSP, may help support the burn specialist’s diagnosis of sepsis and could improve the diagnostic performance of current and future definitions in burn patients.

Sign in / Sign up

Export Citation Format

Share Document