Etudes Musculation : page 33.2

Les bandes élastiques améliorent le squat

23/01/2010 | Accessoires de musculation et Etudes Musculation

 

Les résultats auraient été encore meilleurs si les chercheurs arrêtaient la drogue. Ils ont fait faire un squat à 20 kg avec 100 kg de bande, le délire quoi !

Kinetic and kinematic differences between squats performed with and without elastic bands

Israetel, MA, McBridem, JM, Nuzzo, JL, Skinner, JW, and Dayne, AM.  J Strength Cond Res 24(1): 190-194, 2010

The purpose of this investigation was to compare kinetic and kinematic variables between squats performed with and without elastic bands equalized for total work. Ten recreationally weight trained males completed 1 set of 5 squats without (Wht) and with (Band) elastic bands as resistance. Squats were completed while standing on a force platform with bar displacement measured using 2 potentiometers. Electromyography (EMG) was obtained from the vastus lateralis. Average force-time, velocity-time, power-time, and EMG-time graphs were generated and statistically analyzed for mean differences in values between the 2 conditions during the eccentric and concentric phases. The Band condition resulted in significantly higher forces in comparison to the Wht condition during the first 25% of the eccentric phase and the last 10% of the concentric phase. However, the Wht condition resulted in significantly higher forces during the last 5% of the eccentric phase and the first 5% of the concentric phase in comparison to the Band condition. The Band condition resulted in significantly higher power and velocity values during the first portion of the eccentric phase and the latter portion of the concentric phase. Vastus lateralis muscle activity during the Band condition was significantly greater during the first portion of the eccentric phase and latter portion of the concentric phase as well. This investigation indicates that squats equalized for total work with and without elastic bands significantly alter the force-time, power-time, velocity-time, and EMG-time curves associated with the movements. Specifically, elastic bands seem to increase force, power, and muscle activity during the early portions of the eccentric phase and latter portions of the concentric phase.

Le sport aide à arrêter de fumer

20/01/2010 | Etudes Musculation et Etudes Anti-âge

 

Plus l’intensité d’effort est grande, plus la réduction de l’envie de fumer est importante.

Effects of exercise on cravings to smoke: The role of exercise intensity and cortisol
Authors: Filippe Scerbo a;  Guy Faulkner b;  Adrian Taylor b; Scott Thomas a
Journal of Sports Sciences, Volume 28, Issue 1 January 2010 , pages 11 - 19

Research consistently demonstrates that a bout of moderate exercise alleviates cravings to smoke among abstaining smokers. The aims of this study were to examine whether doses of exercise (moderate or vigorous) reduced cravings differently, and whether reductions in cravings were associated with changes in cortisol concentration. Using a within-participant, crossover design, 18 participants conducted three 15-min treatment sessions on separate days: passive, walking (45-50% heart rate reserve), and running (80-85% heart rate reserve) conditions. Participants rated cravings at baseline, mid-treatment, and 0, 10, 20, and 30 min after each treatment. Salivary cortisol samples were collected at baseline, immediately after, and 30 min after each condition. Significant group time interactions were identified, demonstrating significant reductions in craving items after the walking and running conditions compared with the passive control. No significant differences in craving reductions were found between walking and running conditions. Post hoc comparisons found that running condition cravings to smoke scores were reduced for a longer duration post-treatment than post-walking condition scores. The decline in cortisol concentration was attenuated in the running group only. Vigorous exercise has a similar effect to moderate exercise in terms of the magnitude of craving reduction. However, performing bouts of moderate-intensity exercise may be a better recommendation for reducing cravings.

 

Injection de plaquettes contre les tendinites ?

16/01/2010 | Etudes Musculation et Etudes Compléments alimentaires

 

Une nouvelle étude révèle que les injections de plaquettes ne seraient pas efficaces contre les tendinites :

Platelet-Rich Plasma Injection for Chronic Achilles Tendinopathy
A Randomized Controlled Trial
Robert J. de Vos, MD; Adam Weir, MBBS; Hans T. M. van Schie, DVM, PhD; Sita M. A. Bierma-Zeinstra, PhD; Jan A. N. Verhaar, MD, PhD; Harrie Weinans, PhD; Johannes L. Tol, MD, PhD
JAMA. 2010;303(2):144-149.

Context Tendon disorders comprise 30% to 50% of all activity-related injuries; chronic degenerative tendon disorders (tendinopathy) occur frequently and are difficult to treat. Tendon regeneration might be improved by injecting platelet-rich plasma (PRP), an increasingly used treatment for releasing growth factors into the degenerative tendon.

Objective To examine whether a PRP injection would improve outcome in chronic midportion Achilles tendinopathy.

Design, Setting, and Patients A stratified, block-randomized, double-blind, placebo-controlled trial at a single center (The Hague Medical Center, Leidschendam, the Netherlands) of 54 randomized patients aged 18 to 70 years with chronic tendinopathy 2 to 7 cm above the Achilles tendon insertion. The trial was conducted between August 28, 2008, and January 29, 2009, with follow-up until July 16, 2009.

Intervention Eccentric exercises (usual care) with either a PRP injection (PRP group) or saline injection (placebo group). Randomization was stratified by activity level.

Main Outcome Measures The validated Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire, which evaluated pain score and activity level, was completed at baseline and 6, 12, and 24 weeks. The VISA-A score ranged from 0 to 100, with higher scores corresponding with less pain and increased activity. Treatment group effects were evaluated using general linear models on the basis of intention-to-treat.

Results After randomization into the PRP group (n = 27) or placebo group (n = 27), there was complete follow-up of all patients. The mean VISA-A score improved significantly after 24 weeks in the PRP group by 21.7 points (95% confidence interval [CI], 13.0-30.5) and in the placebo group by 20.5 points (95% CI, 11.6-29.4). The increase was not significantly different between both groups (adjusted between-group difference from baseline to 24 weeks, –0.9; 95% CI, –12.4 to 10.6). This CI did not include the predefined relevant difference of 12 points in favor of PRP treatment.

Conclusion Among patients with chronic Achilles tendinopathy who were treated with eccentric exercises, a PRP injection compared with a saline injection did not result in greater improvement in pain and activity.

En savoir + :  HealthNews

En cas de rupture du grand pectoral, il faut se faire opérer

08/01/2010 | Etudes Musculation

 

Pectoralis Major Muscle Rupture in Athletes : A Prospective Study
Alberto de Castro Pochini, MD†*, Benno Ejnisman, MD†, Carlos Vicente Andreoli, MD†, Gustavo Cara Monteiro, MD†, Antonio Carlos Silva, MD‡, Moises Cohen, MD, PhD† and Walter Manna Albertoni§
Am J Sports Med January 2010 vol. 38 no. 1 92-98

Background In the past 20 years, there has been an increase in the incidence of upper extremity tendinous injuries, especially in sports including strong physical activity, such as in weight lifting, as well as with the concurrent use of anabolic steroids. Today, there are more than 200 cases describing rupture of the pectoralis major muscle in athletes.

Hypothesis Surgical treatment will have a better outcome than nonsurgical treatment in total rupture of the pectoralis major muscle in athletes.

Study Design Cohort study; Level of evidence, 2.

Methods Twenty athletes with pectoralis major muscle (PMM) rupture were studied; 10 had surgical treatment, and the other 10 were treated nonoperatively. The mean age was 32.27 years (range, 27–47 years); all of them were men. The average follow-up was 36 months (range, 48–72 months). Injuries were diagnosed by history, physical examination, and subsidiary tests. Functional evaluation and isokinetic evaluation were performed on all 20 patients.

Results The clinical evaluation revealed
70% (n = 7) excellent, 20% good (n = 2), and 10% poor (n = 1) outcomes for the cases treated with surgery and
20% good (n = 2), 50% fair (n = 5), and 40% poor (n = 4) outcomes for the cases treated nonsurgically.
The isokinetic evaluation at 60-deg/s speed showed a decrease in strength of 53.8% in the nonsurgical group and 13.7% for the surgical group.

Conclusion Total PMM rupture in athletes showed a better functional result after surgical treatment than after nonsurgical treatment.

Électro-stimulation et acide lactique

08/01/2010 | Etudes Musculation

 

On me pique mes idées !

Je crois avoir été le premier à dire qu’il fallait utiliser l’électro-stimulation (EMS) non pas en dehors de l’entraînement classique mais au contraire pendant celui-ci pour un maximum d’effet.

Ici, ils montrent, comme je l’avais dit, que l’EMS est très efficace pour éliminer l’acide lactique après un effort.

Comparison of swim recovery and muscle stimulation on lactate removal after sprint swimming.
Neric, FB, Beam, WC, Brown, LE, and Wiersma, LD.  J Strength Cond Res 23(9): 2560-2567, 2009.

Competitive swimming requires multiple bouts of high-intensity exercise, leading to elevated blood lactate. Active exercise recovery has been shown to lower lactate faster than passive resting recovery but may not always be practical. An alternative treatment, electrical muscle stimulation, may have benefits similar to active recovery in lowering blood lactate but to date is unstudied. Therefore, this study compared submaximal swimming and electrical muscle stimulation in reducing blood lactate after sprint swimming.

Thirty competitive swimmers (19 men and 11 women) participated in the study. Each subject completed 3 testing sessions consisting of a warm-up swim, a 200-yard maximal frontcrawl sprint, and 1 of 3 20-minute recovery treatments administered in random order. The recovery treatments consisted of a passive resting recovery, a submaximal swimming recovery, or electrical muscle stimulation. Blood lactate was tested at baseline, after the 200-yard sprint, and after 10 and 20 minutes of recovery.

A significant interaction (p

< 0.05) between recovery treatment and recovery time was observed. Blood lactate levels for the swimming recovery were significantly lower at 10 minutes (3.50 +/- 1.57 mmol·L-1) and 20 minutes (1.60 +/- 0.57 mmol·L-1) of recovery than either of the other 2 treatments. Electrical muscle stimulation led to a

lower mean blood lactate (3.12 +/- 1.41 mmo.L-1) after 20 minutes of recovery compared with passive rest (4.11 +/- 1.35 mmol·L-1). Submaximal swimming proved to be most effective at lowering blood lactate, but electrical muscle stimulation also reduced blood lactate 20 minutes postexercise significantly better than resting passive recovery. Electrical muscle stimulation shows promise as an alternate recovery treatment for the purpose of lowering blood lactate.

Expérience et temps de repos entre les séries

08/01/2010 | Etudes Musculation

 

Upper And Lower Body Strength Increases Consequent To Different Inter-Set Rest Intervals In Trained Men.

Journal of Strength & Conditioning Research. 24 Supplement 1:1, January 2010.
de Salles, Belmiro Freitas; Simao, Roberto; Miranda, Humberto; Bottaro, Martim; de Souza Bezerra, Ewertton; Fontana, Fabio; Willardson, Jeffrey M

There has been considerable debate about the effectiveness of different rest interval lengths on strength gains. OBJECTIVE: The purpose of the current study was to examine the effects of different rest interval durations on upper- and lower-body strength during and after a 16 week resistance training program. Thirty-six recreationally trained men were randomly assigned to one (G1; n = 12), three (G3; n = 12) or five (G5; n = 12) minutes rest interval groups. Each group performed the same program in a nonlinear periodized training model. Maximal strength was assessed at baseline, mid-point (eight weeks) and post-training (16 weeks) for the bench press and leg press exercises.

For the bench press, significant increases were demonstrated within G3 and G5 at eight weeks and 16 weeks versus baseline (p

< .05). Additionally,

G5 (98.2 +/- 3.7 kg) was significantly stronger than G1 (92.5 +/- 3.8 kg) at 16 weeks (p < .05). For the leg press, significant increases were demonstrated within all groups at eight weeks and 16 weeks versus baseline (p < .05). Additionally, there were significant differences between groups at eight weeks [i.e. G5 (290.8 +/- 23.5 kg) significantly stronger than G1 (251.0 +/- 15.8 kg); p < .01] and 16 weeks [i.e. G3 (305.0 +/- 23.9 kg) and G5 (321.7 +/- 21.7 kg) significantly stronger than G1 (276.7 +/- 10.7 kg); p < .05]. The findings of the current study indicate that longer rest intervals may result in significantly greater increases in upper and lower body strength after the early weeks of training, when compared to shorter rest intervals. Shorter rest intervals can be effective for strength increases in less trained muscles or exercises; this may apply to advanced athletes following a layoff or novice athletes beginning a resistance training program. Longer rest intervals (up to five minutes) are best applied in highly trained muscles and exercises and the window for adaptation narrows.

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