Michael J. Carper

Postprandial metabolism in resistance-trained versus sedentary males

INTRODUCTION This investigation examined if postprandial metabolism differed between resistance-trained [(RT), N = 12] and sedentary [(SED), N = 12] males. A secondary objective was to determine whether different resistance-training programs [bodybuilding (BB), N = 8 and power/weight-lifting (PL), N = 8] resulted in disparate effects on postprandial energy metabolism. METHODS Moderate fat [(MF), 37% carbohydrate, 18% protein, and 45% fat] and high carbohydrate [(HC), 79% carbohydrate, 20% protein, and 1% fat] meals were randomly administered, and postprandial metabolism was measured for 240 min. Carbohydrate oxidation, fat oxidation, diet-induced thermogenesis (DIT), and glucose and insulin areas under the curve (AUC) were calculated. RESULTS Fat oxidization/lean body mass (LBM) was significantly greater in SED after the HC (RT, 0.27 +/- 0.02 g vs SED, 0.33 +/- 0.02 g, P = 0.017) and MF (RT, 0.34 +/- 0.02 g vs SED, 0.39 +/- 0.02 g, P = 0.036) meals. Carbohydrate oxidation/LBM was significantly greater in RT after the HC meal (RT, 0.87 +/- 0.03 g vs SED, 0.74 +/- 0.04 g, P = 0.017) only. DIT and DIT/LBM were significantly greater in RT compared with SED after the HC meal (DIT: RT, 351 +/- 21 kJ vs SED, 231 +/- 23 kJ, P = 0.001; DIT/LBM: RT, 5.25 +/- 0.028 kJ vs SED, 3.92 +/- 0.37 kJ, P = 0.009). The AUC for both glucose and insulin were significantly greater in SED compared with RT in response to the HC meal but not the MF meal. There were no differences in the BB and PL groups for any measured variables in response to either the HC or MF meals. CONCLUSION These data indicate that postprandial metabolism is different between resistance-trained and sedentary males but that no such differences exist with different resistance training styles.

Are Changes in Physical Work Capacity Induced by High-Intensity Functional Training Related to Changes in Associated Physiologic Measures?

High-Intensity Functional Training (HIFT) is a novel exercise intervention that may test body systems in a balanced and integrated fashion by challenging individuals’ abilities to complete mechanical work. However, research has not previously determined if physical work capacity is unique to traditional physiologic measures of fitness. Twenty-five healthy men and women completed a six-week HIFT intervention with physical work capacity and various physiologic measures of fitness assessed pre- and post-intervention. At baseline, these physiologic measures of fitness (e.g., aerobic capacity) were significantly associated with physical work capacity and this relationship was even stronger at post-intervention assessment. Further, there were significant improvements across these physiologic measures in response to the delivered intervention. However, the change in these physiologic measures failed to predict the change in physical work capacity induced via HIFT. These findings point to the potential utility of HIFT as a unique challenge to individuals’ physiology beyond traditional resistance or aerobic training. Elucidating the translational impact of increasing work capacity via HIFT may be of great interest to health and fitness practitioners ranging from strength/conditioning coaches to physical therapists.

EFFECTS OF PLYOMETRIC TRAINING AND RECOVERY ON VERTICAL JUMP PERFORMANCE AND ANAEROBIC POWER

We examined the effects of 2 plyometric training programs, equalized for training volume, followed by a 4-week recovery period of no plyometric training on anaerobic power and vertical jump performance. Physically active, college-aged men were randomly assigned to either a 4-week (n = 19, weight = 73.4 ± 7.5 kg) or a 7-week (n = 19, weight = 80.1 ± 12.5 kg) program. Vertical jump height, vertical jump power, and anaerobic power via the Margaria staircase test were measured pretraining (PRE), immediately posttraining (POST), and 4 weeks posttraining (POST-4). Vertical jump height decreased in the 4-week group PRE (67.8 ± 7.9 cm) to POST (65.4 ± 7.8 cm). Vertical jump height increased from PRE to POST-4 in 4-week (67.8 ± 7.9 to 69.7 ± 7.6 cm) and 7-week (64.6 ± 6.2 to 67.2 ± 7.6 cm) training programs. Vertical jump power decreased in the 4-week group from PRE (8,660.0 ± 546.5 W) to POST (8,541.6 ± 557.4 W) with no change in the 7-week group. Vertical jump power increased PRE to POST-4 in 4-week (8,660.0 ± 546.5 W to 8,793.6 ± 541.4 W) and 7-week (8,702.8 ± 527.4 W to 8,931.5 ± 537.6 W) training programs. Anaerobic power improved in the 7-week group from PRE (1,121.9 ± 174.7 W) to POST (1,192.2 ± 189.1 W) but not the 4-week group. Anaerobic power significantly improved PRE to POST-4 in both groups. There were no significant differences between the 2 training groups. Four-week and 7-week plyometric programs are equally effective for improving vertical jump height, vertical jump power, and anaerobic power when followed by a 4-week recovery period. However, a 4-week program may not be as effective as a 7-week program if the recovery period is not employed.

Validity, Reliability, and Application of the Session-RPE Method for Quantifying Training Loads during High Intensity Functional Training

The session rate of perceived exertion method (sRPE) has often been utilized in sports activities in which quantification of external training loads is challenging. The multi-modal, constantly varied nature of high intensity functional training (HIFT) represents a significant hurdle to calculate external work and the sRPE method may provide an elegant solution to this problem. However, no studies have investigated the psychometric properties of sRPE within HIFT interventions. Twenty-five healthy men and women participated in six weeks of HIFT. Rate of perceived exertion and heart rate were assessed within every training session throughout the duration of the intervention. Compared to criterion heart rate-based measures, we observed sRPE method is a valid tool across individual, group, and sex levels. However, poor reliability in participants’ abilities to correctly match rate of perceived exertion with the relative level of physiologic effort (i.e., percentile of maximum heart rate) currently limits the utility of this strategy within HIFT. When applied, the validity and reliability of the sRPE seem to improve over time, and future research should continue to explore the potential of this monitoring strategy within HIFT interventions.