Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Strength Cond Res ; 34(12): 3498-3505, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29210955

RESUMEN

Boucher, VG, Parent, AA, Miron, FSJ, Leone, M, and Comtois, AS. Comparison between power off-ice test and performance on-ice anaerobic testing. J Strength Cond Res 34(12): 3498-3505, 2020-The importance of specific testing has been shown in ice hockey performance, and the understanding and connection between them may lead to adapting training and follow-up in elite athletes. The aim of this study was to compare 2 off-ice power tests with performances on ice with National Hockey League (NHL) players. The vertical jump and broad jump tests were used for the off-ice evaluations, whereas a modified SAS-40 and a repeated-sprint skate (RSSm) test were used on-ice as performance variables. Thirty-one players (3 goalkeepers, 10 defense players, and 18 forward players) from the NHL performed before preseason training camp. Four evaluation sessions were performed with 48-hour time intervals between them. The results show that the 2 jump types were correlated (r = 0.45 p < 0.01), and there was a significant correlation between the vertical jump and the best SAS-40 time trial for defense players, but not for forward players (r = 0.76 p = 0.02; r = 0.21 p = 0.16, respectively). By contrast, there was a significant correlation between broad jump and best SAS-40 time trial for forward players but not for defensive players (r = 0.75 p < 0.01; r = 0.19 p = 0.28, respectively). In conclusion, results show that specific player ability needs to be taken into consideration when choosing off-ice tests.


Asunto(s)
Rendimiento Atlético , Hockey , Anaerobiosis , Atletas , Prueba de Esfuerzo , Humanos
2.
J Strength Cond Res ; 33 Suppl 1: S194-S201, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30844981

RESUMEN

Ferland, PM and Comtois, AS. Classic powerlifting performance: A systematic review. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to review all scientific publications related to able-body drug-tested classic powerlifting performance since January 1, 2012, and to regroup them into a brief narrative review. Three electronic databases were systematically searched in August 2018 using the wildcard: powerlift*. A manual search was performed from the reference list of all retained articles. The search and selection strategy permitted to gather a total of 16 scientific articles published in peer-reviewed journals. Results show that practitioners should prioritize a low-bar squat and a wide grip bench press because they generally contribute to moving greater loads, bring more attention to preventing injuries, since a fair amount of powerlifters seem to train injured and prioritize a hypertrophy-power-strength model when prescribing 3 times a week daily undulating periodization on nonconsecutive days for squat and bench. Practitioners could also introduce respiratory muscle training, use daily 1 repetition maximum training combined with down sets on experienced athletes and use a rate of perceived exertion scale based on repetitions in reserve combined with an individual velocity profile when prescribing intensity. Before competition, powerlifters seem to taper in this order: the deadlift, the squat, and lastly the bench press. The Slingshot does help to move more weight because it helps to generate more inertia, but it also deactivates the triceps. Finally, the present work was limited by the present literature but could serve as a reference in the field of powerlifting. Further research should include more details about the circumstances under which they were conducted.


Asunto(s)
Rendimiento Atlético , Músculo Esquelético/fisiología , Entrenamiento de Fuerza/métodos , Levantamiento de Peso/fisiología , Ejercicios Respiratorios , Humanos , Fuerza Muscular , Esfuerzo Físico
3.
J Strength Cond Res ; 33(8): 2177-2184, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31344013

RESUMEN

Almansba, R, Boucher, VG, Parent, AA, and Comtois, AS. Repeated linear and quadrangular sprint as a function of anaerobic power. J Strength Cond Res 33(8): 2177-2184, 2019-This investigation aims to study in U17 soccer players the relationships among performance indices of linear or quadrangular (square shape) repeated-sprint bouts (RSBs) and leg muscular power measured with the Wingate test and the squat jump. Seventeen athletes were recruited. Participants were 16 ± 0.35 years old and had a body mass of 66.5 ± 8.69 kg and a height of 175 ± 0.05 cm. All participants performed linear or quadrangular RSBs, the Wingate test, and a vertical jump test. The mean fast linear sprint time was strongly correlated (p < 0.01) with the force and power measured with the vertical jump test (r = -0.68 and -0.75, respectively), whereas the mean linear RSB was weakly correlated with the peak power and fatigue index measured by the Wingate test (r = -0.54 and -0.56, respectively). There was a correlation between quadrangular RSBs performance indices and both Wingate and vertical jump parameters. In addition, there were no correlations (p > 0.05) between indices of the linear RSBs (decrement index, average, and fastest times) and quadrangular RSBs. Moreover, physiological and perceptual responses were significantly higher (p < 0.01) with quadrangular RSBs compared with linear RSBs. These results indicate that the Wingate test and the vertical jump test can be used as a substitute for repeated-sprint performance time. Finally, however, the repeated sprints with or without direction changes are 2 different motor abilities that should be trained independently of one another.


Asunto(s)
Rendimiento Atlético/fisiología , Carrera/fisiología , Fútbol/fisiología , Adolescente , Atletas , Prueba de Esfuerzo , Humanos , Masculino , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Postura
4.
J Strength Cond Res ; 32(12): 3574-3583, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30335713

RESUMEN

Ferland, PM and Comtois, AS. Athletic profile of alpine ski racers: a systematic review. J Strength Cond Res 32(12): 3591-3600, 2018-The purpose of this study was to review all anthropometric and physical test results performed on alpine ski racers that were published in the scientific literature to build an athletic profile specific to the skier's sex and level. Four electronic databases were systematically searched using the following key words: alpine, skiing, and physiology. The manual search was performed through the reference list of all suitable publications, the author's personal collection, and the proceedings of the International Congresses on Science and Skiing. The search and selection strategy permitted to gather data from 28 peer-reviewed publications that were collected on a total of 1,107 skiers coming from 11 different countries. Results of this study present the athletic profile and also review the different testing protocols. Findings show that men generally present higher test results than women and that higher-level ski racers generally present higher test results than lower-level ski racers. The present review should serve as guidelines for professionals working with alpine ski racers because most of the factors presented in the athletic profile have previously been shown to be related with performance. Further research should include more details on the testing protocols used, be directed toward female athletes, and present results from groups of athletes of the same sex and clearly identified as established at a certain level. These measures could help support further theoretical investigations.


Asunto(s)
Antropometría , Aptitud Física , Esquí/fisiología , Atletas , Traumatismos en Atletas , Femenino , Humanos , Masculino , Consumo de Oxígeno
5.
Aging Clin Exp Res ; 29(2): 239-246, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26971801

RESUMEN

The goal of the present research was to compare the bioenergetics variability of walking, during the 6-min walk test (6-MWT) and a multistage incremental shuttle walk test (MISWT) in an active older population. Twenty-two healthy physically active older adults with a group mean age of 70.4 ± 5.8 years completed the 6-MWT and the MISWT. Heart rate (HR), walking speed and walking [Formula: see text]O2 were measured throughout each test with a portable metabolic cart. Strong correlations were found for the [Formula: see text]O2 peak and the walking speed (r = 0.91 and r = 0.89 respectively for 6-MWT and MISWT). Differences in [Formula: see text]O2 peak values were analysed with a paired Student's t test. Repeated measures ANOVA were conducted to detect differences between tests. The Bland and Altman plot indicates that the average difference between both tests was 2.5 ml kg-1 min-1. MISWT [Formula: see text]O2 peak means were significantly greater than the 6-MWT [Formula: see text]O2 peak mean values (21.6 ± 5.3 vs. 18.9 ± 4.5 ml kg-1 min-1) which indicate bioenergetics differences between the two walking tests. Thus, the MISWT and 6-MWT elicited different walking [Formula: see text]O2 peak and HR suggesting that the MISWT field test challenge the participants to a higher level of cardiovascular and respiratory stress. The walking [Formula: see text]O2 peak recorded for the MISWT was significantly greater than the 6-MWT. Consequently, both tests seem to measure different facets of the aerobic capacity. MISWT seems to be a better indicator of maximal aerobic power whereas the 6-MWT provides more relevant information regarding aerobic endurance in aging population.


Asunto(s)
Envejecimiento/fisiología , Umbral Anaerobio/fisiología , Tolerancia al Ejercicio/fisiología , Caminata/fisiología , Anciano , Metabolismo Energético , Femenino , Evaluación Geriátrica/métodos , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Prueba de Paso/métodos , Velocidad al Caminar/fisiología
6.
Int J Exerc Sci ; 17(2): 810-818, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39247059

RESUMEN

Heart rate variability (HRV) is used as a measure of autonomic nervous system (ANS) function and is based on heart rate (HR) beat-to-beat time interval variance analysis. Various techniques are used for recording HR, however, few studies have compared Holter-type recordings vs HR monitors (HRM) during an orthostatic challenge. OBJECTIVES: Compare HRV measures from an electrocardiogram (ECG) Holter and a HRM as a tool for investigating ANS response for post-concussion rehabilitation follow-up. METHODS: Twenty-seven participants (n = 27; 15 females, 12 males), 18 to 35 years old, non-smoking, no history of cardiac illness and physically active (3 times per week, 60 mins, moderate intensity exercise) participated in the study. ECG signals and HRM were recorded beat-to-beat (R-R) simultaneously. A motorized tilt table was set at 0 degree for supine and 85 degrees for standing position. Participants were instructed to remain for 7 minutes in each position. R-R signals from both Holter and Polar HRM recording starting points were matched before further analysis. Bland-Altman plots were used to compare recordings from the Holter (gold standard) and the Polar HRM in both positions. Unpaired t-test was used to compare measurements obtained with both systems. Significance was set at p < 0.05. RESULTS: No significant differences were observed between R-R measurements taken with both systems under equal conditions (supine and standing). Same variables under similar conditions were significantly correlated (p = 0.0001). CONCLUSION: Both recording and analysis systems (Holter vs HRM) yielded comparable results. Thus, both systems appear valid and interchangeable for HRV analysis for measuring orthostatic challenge HRV responses.

7.
J Manipulative Physiol Ther ; 36(1): 44-50, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23380213

RESUMEN

OBJECTIVE: The purpose of this study was to evaluate the effects of chiropractic manipulative treatment on paraspinal cutaneous temperature (PCT) for subjects with chronic low back pain and compare these PCT findings to subjects without chronic low back pain. METHODS: Two groups were created, a symptomatic treatment group (subjects with chronic low back pain, n = 11, 7 males, 4 females) and an asymptomatic, nontreatment group (asymptomatic subjects, n = 10, 6 males, 4 females). Outcomes included the modified Oswestry questionnaire and PCT measurements in the prone position after an 8-minute acclimation period. The treatment group received 9 chiropractic spinal instrument-based manipulative treatments over 2 weeks. Reevaluation was done 2 weeks after the initial evaluation for both groups. RESULTS: The preintervention Oswestry results (29.8% ± 11.8%) for the treatment group were higher than the asymptomatic group (10.2% ± 10.6%). The postintervention Oswestry results for the treatment group were 14.20 % ± 11.5%. The resulting Cohen's effect size of the spinal manipulation on the Oswestry evaluation is 0.58. The preintervention PCT showed higher temperature for the nontreatment group compared with the treatment group. Comparing the levels associated with low back pain, the nontreatment group PCT was stable, varying from 0.01°C to 0.02°C, whereas the treatment group PCT varied from 0.10°C to 0.18°C. The treatment group postintervention PCT showed an increase in temperature after the 9 visits; however, this did not reach the values of the asymptomatic group. CONCLUSION: The PCT readings for subjects with chronic low back pain were lower than the asymptomatic, nontreatment group. The PCT temperature of the treatment group increased after 9 treatments.


Asunto(s)
Dolor Crónico/terapia , Dolor de la Región Lumbar/terapia , Manipulación Quiropráctica , Temperatura Cutánea/fisiología , Dolor Crónico/fisiopatología , Femenino , Humanos , Dolor de la Región Lumbar/fisiopatología , Masculino , Persona de Mediana Edad , Columna Vertebral , Termografía
8.
J Sports Med Phys Fitness ; 63(2): 367-372, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35816147

RESUMEN

BACKGROUND: Triathletes' physiological adaptations to exercise training can have a different impact on cardiac remodeling based on the extreme exercise preparation. Moreover, cardiac remodeling might be different depending on whether triathletes have trained for many years or if they just decided to be more active. Nevertheless, data are limited in amateur endurance athletes and studies about them are key for their safety. Therefore, we investigated the effects of exercise training for a half-ironman on cardiac remodeling. METHODS: A total of 24 amateur athletes underwent a 24-week exercise program and were followed by three-dimensional echocardiography to assess its global impact on cardiac remodeling. Subanalyses were performed based on participants past-training experience (low versus high). RESULTS: We found significant group effects on the right and left ventricle, significant time effect on the right ventricle. No significant interaction effects were observed. We observed significant correlations between the right ventricle, clinical and performance characteristics where the peak power output explained 38% of the variance, while the body surface area, weight and power at the second ventilatory threshold explained 34%, 31% and 30%, respectively. CONCLUSIONS: Changes in cardiac remodeling in response to an exercise program for a half-ironman are not homogeneous across the ventricles and are influenced by participants' past-training experience. This study strengthens our knowledge of extreme exercise training for a half-ironman to further develop better training programs and medical follow-up in amateur triathletes.


Asunto(s)
Resistencia Física , Remodelación Ventricular , Humanos , Resistencia Física/fisiología , Ejercicio Físico/fisiología , Atletas , Ventrículos Cardíacos/diagnóstico por imagen
9.
PLoS Genet ; 5(7): e1000586, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19649303

RESUMEN

Cystic fibrosis (CF) patients often have reduced mass and strength of skeletal muscles, including the diaphragm, the primary muscle of respiration. Here we show that lack of the CF transmembrane conductance regulator (CFTR) plays an intrinsic role in skeletal muscle atrophy and dysfunction. In normal murine and human skeletal muscle, CFTR is expressed and co-localized with sarcoplasmic reticulum-associated proteins. CFTR-deficient myotubes exhibit augmented levels of intracellular calcium after KCl-induced depolarization, and exposure to an inflammatory milieu induces excessive NF-kB translocation and cytokine/chemokine gene upregulation. To determine the effects of an inflammatory environment in vivo, sustained pulmonary infection with Pseudomonas aeruginosa was produced, and under these conditions diaphragmatic force-generating capacity is selectively reduced in Cftr(-/-) mice. This is associated with exaggerated pro-inflammatory cytokine expression as well as upregulation of the E3 ubiquitin ligases (MuRF1 and atrogin-1) involved in muscle atrophy. We conclude that an intrinsic alteration of function is linked to the absence of CFTR from skeletal muscle, leading to dysregulated calcium homeostasis, augmented inflammatory/atrophic gene expression signatures, and increased diaphragmatic weakness during pulmonary infection. These findings reveal a previously unrecognized role for CFTR in skeletal muscle function that may have major implications for the pathogenesis of cachexia and respiratory muscle pump failure in CF patients.


Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Fibrosis Quística/metabolismo , Fibrosis Quística/fisiopatología , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatología , Animales , Calcio/metabolismo , Células Cultivadas , Fibrosis Quística/genética , Fibrosis Quística/inmunología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Citocinas/inmunología , Diafragma/inmunología , Diafragma/metabolismo , Diafragma/patología , Diafragma/fisiopatología , Modelos Animales de Enfermedad , Expresión Génica , Predisposición Genética a la Enfermedad , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Debilidad Muscular , Músculo Esquelético/inmunología , Músculo Esquelético/patología
10.
J Sports Med Phys Fitness ; 62(2): 170-176, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33666073

RESUMEN

BACKGROUND: Isokinetic strength has been useful to assess muscle function related to sports and prevent injuries. The present study measured the isokinetic isometric and concentric shoulder rotators strength, agonist/antagonist ratio, and examined the relationships between isometric and concentric peak torque, and agonist/antagonist ratio in powerlifters compared to a control group. METHODS: The participants were divided into two groups: powerlifters group (N.=14) and physically active group (N.=9). Participants' were evaluated on isokinetic dynamometer for isometric, and concentric (two velocities, 60°/s and 180°/s) strength of shoulder external (ER) internal rotation (IR). Isometric contractions lasted 10 seconds, and concentric modes were 5 repetitions. RESULTS: Bilateral significant differences, between dominant and non-dominant side, were found in ER peak torque at isometric mode in powerlifters group (P=0.021). Powerlifters showed higher IR peak torque at isometric mode in dominant (P=0.040) and non-dominant side (P=0.014) than physically active group. Pearson correlations between isometric peak torque and concentric velocities ranged between 0.49 and 0.89 for powerlifters group, and between 0.73 and 0.93 for physically active group. For agonist/antagonist ratio, pearson correlation ranged between 0.47 and 0.83 for powerlifters group, and between 0.48 and 0.86 for physically active group. CONCLUSIONS: The bilateral differences in ER movement at isometric mode in powerlifters suggest that exercises for shoulder rotators must be included on training for joint safety and balance between sides despite isometric shoulder rotators strength in powerlifters was higher than physically active individuals. Results presented positive correlation between both muscle actions, isometric and concentric, in peak torque and agonist/antagonist ratio.


Asunto(s)
Articulación del Hombro , Hombro , Humanos , Contracción Isométrica , Músculos , Torque
11.
Scand Cardiovasc J ; 45(5): 316-20, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21726156

RESUMEN

OBJECTIVE: The purpose of this study was to investigate the heart rate variability (HRV) profile in obese women displaying the metabolically healthy but obese (MHO) phenotype. DESIGN: We studied 47 obese, sedentary postmenopausal women. Subjects were classified as MHO or at risk based on insulin resistance as assessed with the homeostatic model assessment (HOMA) index. Subjects were divided into tertiles according to HOMA values. Subjects in the lower tertile were categorised as MHO while subjects in the upper 2 tertiles represented at risk subjects. Outcome measures were heart rate variability factors (RR intervals, SDNN, LF, HF, pNN50, RMSSD), body temperature, body composition (DEXA) and a lipid profile as well as glucose and insulin. RESULTS: MHO individuals had significantly lower resting heart rate, body temperature, lean body mass as well as fasting insulin and HOMA levels compared to at risk subjects (p < 0.05). In addition, RR intervals, SDNN and LF were significantly higher in MHO individuals (p < 0.05). Moreover, stepwise regression analysis showed that SDNN was an independent predictor of the variation in HOMA in our cohort. CONCLUSION: Results of the present study indicate that postmenopausal women displaying the MHO phenotype present a favourable HRV profile. Therefore, higher HRV could be associated, at least in part, in the protective profile of MHO individuals.


Asunto(s)
Enfermedades Cardiovasculares/etiología , Estado de Salud , Frecuencia Cardíaca , Obesidad/fisiopatología , Posmenopausia , Absorciometría de Fotón , Anciano , Biomarcadores/sangre , Glucemia/metabolismo , Composición Corporal , Temperatura Corporal , Enfermedades Cardiovasculares/sangre , Enfermedades Cardiovasculares/fisiopatología , Estudios Transversales , Femenino , Humanos , Insulina/sangre , Resistencia a la Insulina , Lípidos/sangre , Persona de Mediana Edad , Obesidad/sangre , Obesidad/complicaciones , Obesidad/diagnóstico por imagen , Fenotipo , Quebec , Análisis de Regresión , Medición de Riesgo , Factores de Riesgo , Conducta Sedentaria
12.
J Sports Med Phys Fitness ; 61(3): 380-385, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33140633

RESUMEN

BACKGROUND: The purpose of this study was to validate the alpine ski racing 90 s box jump field-test (BJ90) with the 90 s Wingate test (W90). METHODS: Fifteen elite alpine ski racers were tested on the BJ90 (0.45 m × 0.75 m × 0.9 m) and the W90 (Ergomedic 894 E Monark; Monark AB, Varberg, Sweden) test in a random order. The number of hits on the BJ90 was written down every 15 s and for the W90 the load (7.5% of body weight) was manually dropped once the subjects reached maximum RPM without resistance. Correlations and partial correlations were calculated with a 2-tailed Pearson correlation analysis. A stepwise forward regression analysis was also performed. RESULTS: Results present significant (P<0.05) correlations and partial correlations adjusted for body weight between the total number of hits on the BJ90 and W90 peak W, peak W/kg, mean W and mean W/kg as well as with the number of hits and W90 Mean W and mean W/kg between each 15 s time slot. A linear regression predictive equation for mean relative power (W/kg) generated from the BJ90 was established: mean relative power (W/kg)=0.055*total hits+1.080 (r=0.79, P<0.001; total hits with mean W/kg). A stepwise forward regression equation for mean absolute power (W) generated from the BJ90 was also established: mean absolute power (W)=2.305*number of hits+5.081*body weight in kg-1 -169.8 (R=0.964, P<0.001, SEE=23.56). CONCLUSIONS: Practitioners could use the BJ90 to assess alpine skiers lower body power as previous research showed that both are correlated with performance and are able to discriminate skier level.


Asunto(s)
Esquí/fisiología , Peso Corporal , Femenino , Humanos , Masculino
13.
FASEB Bioadv ; 3(8): 639-651, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34377959

RESUMEN

Duchenne muscular dystrophy (DMD) is a genetic disorder that results in the absence of dystrophin, a cytoskeletal protein. Individuals with this disease experience progressive muscle destruction, which leads to muscle weakness. Studies have been conducted to find solutions for the relief of individuals with this disease, several of which have shown that utrophin, a protein closely related to dystrophin, when overexpressed in mdx neonatal mice (the murine model of DMD), is able to prevent the progressive muscle destruction observed in the absence of dystrophin. Furthermore, recent studies have shown that L-arginine induces utrophin upregulation in adult mdx mice. We hypothesized that L-arginine treatment also induces utrophin upregulation to prevent the development of muscle weakness in neonatal mdx mice. Hence, L-arginine should also prevent progressive muscle destruction via utrophin upregulation in mdx neonatal mice. Mdx neonatal mice were injected intraperitoneally daily with 800 mg/kg of L-arginine for 6 weeks, whereas control mice were injected with a physiological saline. The following experiments were performed on the tibialis anterior (TA) muscle: muscle contractility and resistance to mechanical stress; central nucleation and peripheral nucleation, utrophin, and creatine kinase quantification as well as a nitric oxide (NO) assay. Our findings show that early administration of L-arginine in mdx neonatal mice prevents the destruction of the tibialis anterior (TA) muscle. However, this improvement was related to nitric oxide (NO) production rather than the expected utrophin upregulation.

14.
J Sports Med Phys Fitness ; 61(4): 551-561, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32734752

RESUMEN

INTRODUCTION: The goal of this systematic and umbrella review was to regroup all systematic reviews, non-systematic reviews and all original articles into one convenient publication that would facilitate the theoretical and applied scientific investigations directed on cannabis consumption and exercise performance, to update current findings on the matters, and assess evidence quality. EVIDENCE ACQUISITION: The systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method. A computer-based systematic search was conducted in September 2019 through the Pubmed, Scopus and SPORTDiscus databases. The reliability of the systematic search was assured by having the article selection process entirely repeated by a second author. Strength of evidence of the selected articles was assesses using a modified version of the Downs and Black Checklist. EVIDENCE SYNTHESIS: The systematic search yielded a total of 8 peer-reviewed publications as well as 10 literature reviews. Results show that cannabis consumption prior to exercise induces decrements in performance (reduced ability to maintain effort, physical/maximal work capacity), undesired physiological responses (increased heart and breathing rate as well as myocardial oxygen demand) and neurological effects on balance (increased sway). CONCLUSIONS: Based on the articles included in this review, the authors conclude that cannabis consumption has an ergolytic effect on exercise performance and therefore does not act as a sport performance enhancing agent as raised by popular beliefs. Thus, cannabis consumption prior to exercise should be avoided in order to maximize performance in sports. Further research should mimic modern THC dosage (150 mg).


Asunto(s)
Rendimiento Atlético/fisiología , Cannabinoides/farmacología , Cannabis/efectos adversos , Cannabinoides/administración & dosificación , Humanos , Uso de la Marihuana/efectos adversos , Reproducibilidad de los Resultados
15.
J Manipulative Physiol Ther ; 33(3): 238-40, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20350679

RESUMEN

OBJECTIVE: The goal of this pilot study was to measure paraspinal cutaneous temperature (PCT) in the prone vs standing position. METHODS: Ten symptom-free participants were evaluated. Paraspinal cutaneous temperature was recorded. Subjects were acclimated to the treatment room in a prone position for 8 minutes before the PCT was measured. After the prone PCT reading, patients stood. A standing PCT measurement was then taken. RESULTS: Paraspinal cutaneous temperature was marginally warmer when subjects were standing vs prone (PCT difference, 0.25 degrees C +/- 0.64 degrees C and 0.62 degrees C +/- 0.67 degrees C for left and right sides, respectively). The right and left side differential was the same in the prone and standing positions. There was a positive Pearson correlation (0.802-0.803; P < .000) between the standing and prone positions for both left and right sides. CONCLUSION: There are no differences between the prone or standing PCT measures if symptom-free subjects are given 8 minutes to acclimate before recording PCT measures.


Asunto(s)
Temperatura Corporal , Quiropráctica/métodos , Posición Prona , Piel , Conductividad Térmica , Termografía/métodos , Adulto , Femenino , Humanos , Masculino , Proyectos Piloto , Postura , Columna Vertebral/fisiología
16.
J Manipulative Physiol Ther ; 33(4): 308-14, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20534318

RESUMEN

OBJECTIVE: The purpose of this study was to investigate local paraspinal cutaneous temperature (CT) modifications after spinal manipulative therapy at L5. METHODS: Twenty subjects with acute low back symptoms were randomly assigned to either a treatment or a sham group (n = 10 per group). Subjects underwent an 8-minute acclimatizing period. Temperature was measured bilaterally with infrared cameras at the L5 level. In the treatment group, a traditional chiropractic manipulation (lumbar roll technique with a pisiform contact on the ipsilateral mamillary of L5) was delivered, whereas with the sham group, the same technique was used, but no thrust was applied. Cutaneous temperature control measurements were taken 2 minutes before (t(-2)) and immediately after the intervention (t(0)) and at 1, 3, 5, and 10 minutes postintervention (t(1), t(3), t(5), and t(10), respectively). RESULTS: At t(0), CT in the treatment group on the treatment side (ipsilateral side) warmed up by 0.2 degrees F, whereas in the sham group, there were no significant temperature modifications on either side. At t(3) relative to t(0), CT in the treatment group on the treatment side warmed by approximately 0.6 degrees F, whereas the contralateral side (nontreatment side) cooled. In the treatment group, significant differences were noted between sides (F = 13.36, P = .002, P = .932) and sides x times (F = 2.97, P = .016, P = .838). CONCLUSION: The effects of a lumbar spine manipulation appear noticeable by changes in paraspinal CT measurements at the level of L5. However, the meaning and mechanisms of CT modifications at L5 are still being investigated.


Asunto(s)
Dolor de la Región Lumbar/terapia , Manipulación Quiropráctica , Manipulación Espinal , Temperatura Cutánea , Enfermedad Aguda , Adulto , Análisis de Varianza , Factores de Confusión Epidemiológicos , Femenino , Humanos , Dolor de la Región Lumbar/fisiopatología , Vértebras Lumbares , Masculino , Persona de Mediana Edad , Proyectos de Investigación , Columna Vertebral
17.
J Sports Med Phys Fitness ; 60(3): 407-416, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31663317

RESUMEN

BACKGROUND: The purpose of this study was to conduct a detailed body composition analysis by Dual-Energy X-Ray Absorptiometry (DEXA scan) on classic powerlifters to understand better the relationship between various body composition variables and maximal strength. METHODS: Fifteen drug-free classic powerlifters (9 males and 6 females) underwent a DEXA scan and absolute (kg) and relative (Wilks) maximal strength from all 3 powerlifting events (squat, bench and deadlift) was registered from the previous provincial championship. A 2 tailed Pearson correlation analysis was conducted in order to present the relationships between body composition variables and performance measures. RESULTS: The main outcome of the present study is that experience in resistance training (r=0.52 to 0.74), lean body tissue (r= 0.61 to 0.95), arms mass (r=0.57 to 0.86), legs mass (r=0.53 to 0.63), bone mineral content (BMC) (r=0.52 to 0.91) and bone mineral density (BMD) (r=0.53 to 91) measures were significantly correlated (P<0.05) with most absolute (kg) and relative (Wilks) maximal strength measures. CONCLUSIONS: The results of the present study could guide practitioners working with athletes aged between 22 and 35 years old practicing sports with higher risks of fractures (e.g., alpine skiing) to potentially utilize the squat, the bench press and the deadlift not only to build strength in order to increase sport performance, but also to increase BMC and BMD of their athletes trough heavy eccentric loading to help reduce the risks of fractures. Further studies should be directed towards interventions trying to reveal that some type of relationship does exist between BMC, BMD and powerlifting performance and in what direction.


Asunto(s)
Composición Corporal , Fuerza Muscular/fisiología , Entrenamiento de Fuerza/métodos , Levantamiento de Peso/fisiología , Absorciometría de Fotón , Adulto , Brazo/anatomía & histología , Brazo/fisiología , Densidad Ósea , Femenino , Fracturas Óseas/prevención & control , Humanos , Pierna/anatomía & histología , Pierna/fisiología , Masculino , Adulto Joven
18.
Int J Exerc Sci ; 13(5): 615-632, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32509130

RESUMEN

The purpose of this study was to better understand the psychological momentum (PM) in varsity cross-country competitive runners during a 3000 m selection trials. A sequential explanatory mixed methods design was used: recruitment trial race day (quantitative) and interview day (qualitative + maximal aerobic running speed [MARS]). Sample was consisted of fifteen university distance runners (n = six women [25.9 ± 7.0 years old; 22.2 ± 1.8 BMI] and nine men [23.2 ± 2.4 years old; 22.6 ± 1.6 BMI]). During the recruitment trial race, athletes' MARS was measured and used to create a performance index (PERFI) relative to selected moments. Also, the recruitment trial race was filmed. During the interviews, the recorded film was used to support athletes in the identification of key moments of the race, as well as to discuss positive and negative PM. PM was both defined by participants and devised by three themes: psychological, physiological and psychophysiological change. A significant PERFI difference (p < 0.001) was observed between positive (97.04 ± 5.88%) and negative (108.46 ± 7.76%) moments of PM. The results of PERFI for men and women athletes were not significantly different (p = 0.118). The PERFI standard deviation for women was not correlated (r2 = 0.26, p = 0.30) with the 3000 m time trial performance, but it was significantly correlated for men (r2 = 0.94, p < 0.001). The results of the present study could help developing interventions to focus on specific elements of the momentum such as race management/strategy, the attentiveness of the runner during the race and other elements of mental and physical preparation of the athletes.

19.
Int J Exerc Sci ; 13(6): 766-777, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32509136

RESUMEN

Long distance triathlon has gained in popularity amongst the general population. Coaches establish training programs based upon their knowledge, personal experience and on current training principles. The goal was to observe the effect of a triathlon training program for a half Ironman event in neophyte amateur athletes. A specific triathlon training program was followed from February to June 2016 by a group preparing for their first half ironman. Out of the 32 participants (19 Males and 13 Females; mean age of 39 ± 9.9 years old; body weight of 72.7 ± 13.4 kg and a height of 171.5 ± 10.2 cm), only one did not complete the event. A mean training volume of 410 ± 201 min per week led to a mean finishing time of 6 hours 28 minutes. The training program significantly increased the maximal oxygen consumption (45.9 ± 8.2 to 48.6 ± 7.5 ml/kg/min, p =0.002) and the maximal power output (293.1 ± 63.7 to 307.8 ± 58.7 W, p < 0.001). The absolute oxygen consumption and power output at both ventilatory thresholds also significantly increased (VT1: 2.2 ± 0.4 to 2.5 ± 0.5 L, p = 0.001; 157.8 ± 41.8 to 176.7 ± 41.1 W p = 0.009 and VT2: 2.9 ± 0.4 to 3.0 ± 0.4 L, p = 0.017; 229.3 ± 62.0 to 244.8± 55.2 W, p = 0.022 ). A significant diminution of waist circumference was observed (83.2 ± 10.0 to 81.8 ± 9.5 cm, p = 0.032) with no significant changes in body weight. Thus, a 24-week specific training program appears to be safe and efficient for amateur athletes aiming to finish their first half- Ironman event.

20.
J Manipulative Physiol Ther ; 32(4): 277-86, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19447264

RESUMEN

BACKGROUND: The purpose of this study was to examine heart rate variability (HRV) in the presence or the absence of pain in the lower back, while receiving one chiropractic treatment at L5 from either a manually assisted mechanical force (Activator) or a traditional diversified technique spinal manipulation. METHODS: A total of 51 participants were randomly assigned to a control (n = 11), 2 treatment, or 2 sham groups (n = 10 per group). Participants underwent an 8-minute acclimatizing period. The HRV tachygram (RR interval) data were recorded directly into a Suunto watch (model T6; FitzWright Company Ltd, Langley, British Columbia, Canada). We analyzed the 5-minute pretreatment and posttreatment intervals. The spectral analysis of the tachygram was performed with Kubios software. RESULTS: All groups decreased in value except the control group that reacted in the opposite direction, when comparing the pretests and posttests for the high-frequency component. The very low frequency increased in all groups except the control group. The low frequency decreased in all groups except the sham pain-free group. The low frequency-high frequency ratio decreased in the treatment pain group by 0.46 and in the sham pain-free group by 0.26. The low frequency-high frequency ratio increase was 0.13 for the sham pain group, 0.04 for the control group, and 0.34 for the treatment pain-free group. The mean RR increased by 11.89 milliseconds in the sham pain-free group, 18.65 milliseconds in the treatment pain group, and 13.14 milliseconds in the control group. The mean RR decreased in the treatment pain-free group by 1.75 milliseconds and by 0.01 milliseconds in the sham pain group. CONCLUSION: Adjusting the lumbar vertebrae affected the lumbar parasympathetic nervous system output for this group of participants. Adaptation in the parasympathetic output, reflected by changes in high frequency, low frequency, and very low frequency, may be independent of type of adjustment. Therefore, the group differences found in the modulation of the HRV would seem to be related to the presence or absence of pain. The autonomic nervous system response may be specific and sensitive to its effectors organ.


Asunto(s)
Quiropráctica , Frecuencia Cardíaca/fisiología , Dolor Pélvico/terapia , Adulto , Sistema Nervioso Autónomo/fisiopatología , Electrocardiografía , Electromiografía , Femenino , Humanos , Masculino , Manipulación Espinal , Dolor Pélvico/fisiopatología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA