Thomas J. Pujol

Potential safety issues with blood flow restriction training.

The focal point of previous literature was establishing the efficacy of blood flow restriction training with respect to muscular strength, muscular hypertrophy, and muscular endurance. After mounting evidence supporting the efficacy of low‐intensity blood flow restriction training, research has shifted to the overall safety of this training modality. The aim of this review was to summarize the research on the overall safety of blood flow restriction training, focusing on the cardiovascular system (central and peripheral), muscle damage, oxidative stress, and nerve conduction velocity responses compared with those observed with regular exercise. Although still sparse, the blood flow restriction training research thus far is promising with respect to safety outcomes. Individuals respond similarly to blood flow restriction training and to regular exercise; however, longer term studies are required to better understand the chronic effects of low‐intensity blood flow restriction training and possible safety issues.

The Use of Occlusion Training to Produce Muscle Hypertrophy

LOW-INTENSITY OCCLUSION (50-100 MM HG) TRAINING PROVIDES A UNIQUE BENEFICIAL TRAINING MODE FOR PROMOTING MUSCLE HYPERTROPHY. TRAINING AT INTENSITIES AS LOW AS 20% 1 REPETITION MAXIMUM WITH MODERATE VASCULAR OCCLUSION RESULTS IN MUSCLE HYPERTROPHY IN AS LITTLE AS 3 WEEKS. A TYPICAL EXERCISE PRESCRIPTION CALLS FOR 3 TO 5 SETS TO VOLITIONAL FATIGUE WITH SHORT REST PERIODS. THE METABOLIC BUILDUP CAUSES POSITIVE PHYSIOLOGIC REACTIONS, SPECIFICALLY A RISE IN GROWTH HORMONE THAT IS HIGHER THAN LEVELS FOUND WITH HIGHER INTENSITIES. OCCLUSION TRAINING IS APPLICABLE FOR THOSE WHO ARE UNABLE TO SUSTAIN HIGH LOADS DUE TO JOINT PAIN, POSTOPERATIVE PATIENTS, CARDIAC REHABILITATION, ATHLETES WHO ARE UNLOADING, AND ASTRONAUTS.

Influence of music on Wingate Anaerobic Test performance.

While several studies have investigated the effects of music on cardiovascular endurance performance and perceived exertion during exercise of moderate intensity, few studies have investigated such effects on supramaximal exercise bouts. The purpose of the present study was to assess whether music affects performance on the Wingate Anaerobic Test. Each of the 12 men and 3 women were required to report to the laboratory on two occasions, once for tests in the music condition and once for tests in the nonmusic condition. Conditions were randomly ordered. All music selections were set at the same tempo. On each test day subjects performed a series of three Wingate Anaerobic Tests with 30-sec. rests in between. On Test 3 subjects were asked to continue pedaling until fatigued. Mean Power Output, Maximum Power Output, Minimum Power Output, and Fatigue Index were compared between conditions for each test using a repeated-measures analysis of variance. Time to fatigue on Trial 3 compared by analysis of variance gave no significant differences between conditions for any measures.

The Acute Response of Practical Occlusion in the Knee Extensors

Loenneke, JP, Kearney, ML, Thrower, AD, Collins, S, and Pujol, TJ. The acute response of practical occlusion in the knee extensors. J Strength Cond Res 24(10): 2831-2834, 2010-Training at low intensities with moderate vascular occlusion results in increased muscle hypertrophy, strength, and endurance. Elastic knee wraps, applied to the proximal portion of the target muscle, might elicit a stimulus similar to the KAATSU Master Apparatus. The purpose of this study was to test the hypothesis that intermittently occluding the leg extensors with elastic knee wraps would increase whole-blood lactate (WBL) over control (CON). Twelve healthy men and women participated in this study (age 21.2 ± 0.35 years, height 168.9 ± 2.60 cm, and body mass 71.2 ± 4.16 kg). One repetition maximum (1RM) testing for the leg extensors was performed on a leg extension machine for the first trial, followed by occlusion (OCC) and CON trials. Four sets of leg extension exercise (30-15-15-15) were completed with 150-second rest between sets at 30% 1RM. Whole-blood lactate, heart rate (HR), and ratings of perceived exertion (RPEs) were measured after every set of exercise and 3 minutes postexercise. Data were analyzed using repeated-measures analysis of variance with statistical significance set at p ≤ 0.05. Whole-blood lactate increased in response to exercise (p = 0.01) but was not different between groups (OCC 6.28 ± 0.66 vs. CON 5.35 ± 0.36 mmol·L−1, p = 0.051). Heart rate (OCC 128.86 ± 4.37 vs. CON 119.72 ± 4.10 b·min−1) was higher with OCC from sets 2-4 (p ≤ 0.03), with no difference 3 minutes postexercise (p = 0.29). Rating of perceived exertion was higher with OCC after every set (OCC 15.10 ± 0.31 vs. CON 12.16 ± 0.50, p = 0.01). In conclusion, no differences exist for WBL between groups, although there was a trend for higher levels with OCC. The current protocol for practical occlusion did not significantly increase metabolic stress more than normal low-intensity exercise. This study does not support the use of knee wraps as a mode of blood-flow restriction.

Blood flow restriction reduces time to muscular failure

Abstract Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low-intensity exercise likely requires more repetitions and individuals with injuries may be incapable of sustaining the mechanical stress to reach failure. The aim of this study was to determine if knee wraps provide a stimulus to decrease time to failure. Twenty healthy individuals participated in a randomized crossover study consisting of three trials. The first trial was used to determine one-repetition maximum (1-RM) on leg extension. Participants were then assigned to a blood flow restriction or control group. After trial 2, participants crossed over to the opposite trial. Knee wraps were placed around the upper thigh of each leg during blood flow restriction. Leg extensions were completed at 30% 1-RM until failure. A rating of perceived exertion was taken after exercise and whole blood samples were taken before, after, and 3 min after exercise for the determination of lactate. Repetitions until failure and total work were significantly lower with practical blood flow restriction compared with the control trial. Metabolic stress as measured by whole blood lactate was higher immediately after muscular failure in the control compared with the blood flow restriction trial, but not so 3 min after exercise. There were no differences in ratings of perceived exertion. In conclusion, knee wraps provide a stimulus for blood flow restriction allowing failure to occur sooner with similar metabolic stress after reperfusion. However, similar perceptual responses despite the lower workload with blood flow restriction may limit its application to the highly motivated.

Blood flow-restricted walking does not result in an accumulation of metabolites.

The American College of Sports Medicine recommends lifting a weight of at least 70% of one’s concentric one repetition maximum to achieve muscular hypertrophy as it is believed that anything below this intensity does not produce significant muscle growth. Recent studies have found muscle hypertrophy to occur with low‐intensity ‘aerobic–like’ exercise with the application of blood flow restriction (BFR) to the limbs. Previous research with low load resistance training has shown that elastic knee wraps provide a practical means to induce elevations in whole blood lactate (WBL), which has been hypothesized to result in many of the adaptations observed with this type of exercise. However, this has yet to be investigated with low‐intensity walking. Thus, the purpose of this paper was to determine the degree to which WBL increases with practical BFR walking. Exercise consisted of five 2‐min bouts of walking at 75 m per min on a motor‐driven treadmill with a 1‐min rest period following each exercise bout. Participants completed the walking with (BFR) and without [control (CON)] restriction to the upper thigh in a randomized order. Practical BFR with elastic knee wraps did statistically increase WBL compared with CON; however, this was not considered a real change because the minimal difference between conditions was not exceeded. In conclusion, metabolic stress is not increased following practical BFR walking exercise. This study may provide an explanation for the lower hormone response observed with BFR walking and provide further evidence that mechanisms other than metabolic accumulation exist with BFR.

Time under tension decreased with blood flow–restricted exercise

Objectives: Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low‐intensity exercise likely requires more time under tension and those with injuries may be incapable of sustaining the mechanical stress to reach failure. Design: The purpose was to determine whether elastic knee wraps (KW) provide a stimulus to decrease time under tension and overall volume of work while maintaining a similar level of metabolic stress. Methods: Thirteen healthy subjects participated in a randomized crossover study consisting of three trials. The first determined 1 repetition maximum (1RM) on the bilateral leg extension. Subjects were then assigned to a blood flow restriction (BFR) or control (CON) group. After trial 2, subjects crossed over to the opposite trial. KW were placed around the thigh of each leg during BFR. Leg extensions were completed at 30% 1RM until failure. Whole blood lactate (WBL) was taken pre‐, post‐, and 3 and 5 min postexercise. Heart rate (HR) was measured before, following the first and second sets, and 3 and 5 min postexercise. Results: This study found KW provide a BFR stimulus allowing failure to occur sooner with similar metabolic stress postreperfusion. There were no differences in HR at any time point. Conclusions: These results may benefit populations that cannot sustain the mechanical stress of high‐intensity exercise or low‐intensity exercise that requires a longer sustained time under tension.

Validity and reliability of an ultrasound system for estimating adipose tissue

When health professionals measure the fitness levels of clients, body composition is usually estimated. In field settings, body composition is commonly estimated with skinfolds or bioelectrical impedance analysis. Recently, a portable ultrasound device has been manufactured to estimate what percentage of body mass is composed of adipose tissue (AT%). A reported advantage of using ultrasound is that inter‐ and intrarater variations may be minimized when compared with the skinfold technique. Therefore, the purpose of this pilot study was twofold; 1) to determine the validity of a portable ultrasound device compared with skinfolds and 2) determine the reliability of the portable ultrasound device. Participants had their measurements taken in the following order: urine specific gravity, body mass, height, skinfolds and ultrasound determined. Participants had their urine specific gravity and ultrasound determined AT% estimates measured again 48 h later. The current pilot study found that the ultrasound was not a valid estimate of AT% when compared with the skinfold estimate (TE > 4%). In addition, the 1‐site estimate from the ultrasound was more reliable than the 3‐site estimate of AT%. These data are of importance to practitioners because it demonstrates that while the ultrasound is not a valid estimate compared with skinfolds, the 1‐site estimate may be able to track changes in AT% over time, making the ultrasound an option for assessing changes in body composition.

Reliability of field methods for estimating body fat.

When health professionals measure the fitness levels of clients, body composition is usually estimated. In practice, the reliability of the measurement may be more important than the actual validity, as reliability determines how much change is needed to be considered meaningful. Therefore, the purpose of this study was to determine the reliability of two bioelectrical impedance analysis (BIA) devices (in athlete and non‐athlete mode) and compare that to 3‐site skinfold (SKF) readings. Twenty‐one college students attended the laboratory on two occasions and had their measurements taken in the following order: body mass, height, SKF, Tanita body fat‐350 (BF‐350) and Omron HBF‐306C. There were no significant pairwise differences between Visit 1 and Visit 2 for any of the estimates (P>0·05). The Pearson product correlations ranged from r = 0·933 for HBF‐350 in the athlete mode (A) to r = 0·994 for SKF. The ICCs ranged from 0·93 for HBF‐350(A) to 0·992 for SKF, and the MDs ranged from 1·8% for SKF to 5·1% for BF‐350(A). The current study found that SKF and HBF‐306C(A) were the most reliable (<2%) methods of estimating BF%, with the other methods (BF‐350, BF‐350(A), HBF‐306C) producing minimal differences greater than 2%. In conclusion, the SKF method presented with the best reliability because of its low minimal difference, suggesting this method may be the best field method to track changes over time if you have an experienced tester. However, if technical error is a concern, the practitioner may use the HBF‐306C(A) because it had a minimal difference value comparable to SKF.

Quality protein intake is inversely related with abdominal fat

Dietary protein intake and specifically the quality of the protein in the diet has become an area of recent interest. This study determined the relationship between the amount of quality protein, carbohydrate, and dietary fat consumed and the amount of times the ~10 g essential amino acid (EAA) threshold was reached at a meal, with percent central abdominal fat (CAF). Quality protein was defined as the ratio of EAA to total dietary protein. Quality protein consumed in a 24-hour period and the amount of times reaching the EAA threshold per day was inversely related to percent CAF, but not for carbohydrate or dietary fat. In conclusion, moderate to strong correlations between variables indicate that quality and distribution of protein may play an important role in regulating CAF, which is a strong independent marker for disease and mortality.