The purpose was to determine repetitions to failure and perceptual responses to exercise with and without occlusion. 15 subjects participated in a randomized crossover study of 3 trials. The first determined one repetition maximum (1RM) on the leg extension. Subjects were then assigned to an occlusion (OCC) or control (CON) group. After trial 2, subjects crossed over to the opposite trial. Knee wraps (KW) were placed around the upper thigh of each leg during OCC. Subjects completed 2 sets of leg extensions to failure at 30% 1RM, with 30 s rest between sets. Ratings of perceived exertion (RPE) and pain (P) were taken following each set. Data were analyzed using paired sample t-tests with an alpha level of 0.01. OCC repetitions were lower for the first and second set compared to CON (p=0.001). Total work completed was significantly lower with OCC compared to CON (p=0.001). OCC RPE were higher for both the first (p=0.01) and second set (p=0.003) compared to CON. P was not different following one set but was higher with OCC over CON following the second (p=0.009). In conclusion, KW provide an OCC stimulus allowing failure to occur sooner. However, the higher perceptual responses with OCC may limit its application to the highly motivated.

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.

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.

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.

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.

The purpose of this study was to determine the extent to which scientific research influences college strength and conditioning coaching practices and to determine the training methods utilized. A total of 321 surveys were mailed to Division I strength and conditioning coaches, and the response rate was 42.7% (137 of 321 surveys). Results indicate that all subjects held a baccalaureate degree, the majority in a human performance-related field, and that 75% were Certified Strength and Conditioning Specialist (CSCS) certified. The respondents' most widely utilized professional resources were the Strength and Conditioning Journal (94%) and other collegiate coaches and programs (93%). Forty-seven percent of respondents indicated that other collegiate coaches and their programs were the most important sources of knowledge outside of formal education. The majority indicated that they used a periodization protocol (93%) utilizing multiple sets (97%), plyometrics (90%), explosive movements (88%), and Olympic lifts (85%). Respondents tend to rely on sources of information that may not be defined as scientific, as evidenced by the low priority given to peer-reviewed literature. Respondents also tend to employ the methods they utilized as athletes. Reliance on these sources may not take advantage of advances made through scientific research in exercise physiology, biomechanics, and more specifically the area of strength and conditioning.

Syed-Abdul, MM, Soni, DS, Miller, WM, Johnson, RJ, Barnes, JT, Pujol, TJ, and Wagganer, JD. Traditional versus suspended push-up muscle activation in athletes and sedentary women. J Strength Cond Res 32(7): 1816-1820, 2018-Many strength training programs incorporate push-up exercises, which primarily activate upper-body muscles. Past data support the fact that shoulder girdle muscles (i.e., triceps (T) and anterior deltoids [AD]) exhibit greater electromyography (EMG) activity when a push-up is performed on an unstable (i.e., suspended [SP]) vs. stable (i.e., traditional [TD]) surface (). Sixty-nine healthy female volunteers (soccer players [SO], n = 24; gymnasts [GY], n = 21; sedentary [SE], n = 24) performed three TD and three SP push-ups. Muscle activation, expressed as absolute integral (mV), was measured using EMG analysis. Significant increases in muscle activation were exhibited by GY (TD: p < 0.01 and SP: p < 0.001) and SO (TD: p < 0.05 and SP: p < 0.05) compared to SE for the T muscle. Only SO (p < 0.05) exhibited significantly higher muscle activation during the SP versus TD. For the AD, values were significantly higher for SO (TD: p < 0.001 and SP: p < 0.001) and GY (TD: p < 0.01 and SP: p < 0.01) compared to the SE group. In addition, significantly higher values were exhibited by SO compared with GY during TD push-ups (p < 0.01). Both the SO (p < 0.05) and GY (p < 0.05) group exhibited significantly higher values during SP versus TD push-ups. Finally, values were significantly higher for the AD compared to the T muscle only in the SO group during TD (p < 0.01) and SP (p < 0.05) push-ups. Data from this study for trained women (i.e., SO) are consistent with previous studies, whereas for untrained women (i.e., SE) the findings differed during TD and SP push-ups for both muscles. Differences were also observed between female SO and GY are unexplainable and therefore need further investigation.

When assessing the fitness levels of athletes, body composition is usually estimated, as it may play a role in athletic performance. Therefore, the purpose of this study was to determine the validity of bioelectrical impedance analysis (BIA) and skinfold (SKF) methods compared with dual-energy X-ray absorptiometry (DXA) for estimating percent body fat (%BF) in Division 1 collegiate baseball players (n = 35). The results of this study indicate that the field methods investigated were not valid compared with DXA for estimating %BF. In conclusion, this study does not support the use of the TBF-350, HBF-306, HBF-500, or SKF thickness for estimating %BF in collegiate baseball players. The reliability of these BIA devices remains unknown; therefore, it is currently uncertain if they may be used to track changes over time.