This study was undertaken to determine whether combined elastic and free weight resistance (CR) provides different strength and power adaptations than free weight resistance (FWR) training alone. Forty-four young (age 20 +/- 1 years), resistance-trained (4 +/- 2 years' experience) subjects were recruited from men's basketball and wrestling teams and women's basketball and hockey teams at Cornell University. Subjects were stratified according to team, then randomly assigned to the control (C; n = 21) or experimental group (E; n = 23). Before and after 7 weeks of resistance training, subjects were tested for lean body mass, 1 repetition maximum back squat and bench press, and peak and average power. Both C and E groups performed identical workouts except that E used CR (i.e., elastic resistance) for the back squat and bench press, whereas the C group used FWR alone. CR was performed using an elastic bungee cord attached to a standard barbell loaded with plates. Elastic tension was accounted for in an attempt to equalize the total work done by each group. Statistical analyses revealed significant (P < 0.05) between-group differences after training. Compared with C, improvement for E was nearly three times greater for back squat (16.47 +/- 5.67 vs. 6.84 +/- 4.42 kg increase), two times greater for bench press (6.68 +/- 3.41 vs. 3.34 +/- 2.67 kg increase), and nearly three times greater for average power (68.55 +/- 84.35 vs. 23.66 +/- 40.56 watt increase). Training with CR may be better than FWR alone for developing lower and upper body strength, and lower body power in resistance-trained individuals. Long-term effects are unclear, but CR training makes a meaningful contribution in the short term to performance adaptations of experienced athletes.

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The purpose of the study was to compare changes in running economy, foot impact shock, run performance, and resting heart rate and blood pressure elicited by increases in training volume via run training (RT) and cross training (CT). After 30 d of normal training (NT), male runners (N = 11) completed two 10 d periods of increased training each preceded by 14 d of reduced training (80% NT). Subjects ran 10 consecutive days in the afternoon (100% of NT) and performed 8 additional workouts in the morning (100% of NT). The morning sessions were performed on a cycle ergometer (CT) or a treadmill (RT). Running economy, foot impact shock and lactate were assessed during submaximal running (3.9 +/- 0.06 m.sec-1) at D0 and D11. Following the submaximal run, subjects completed a simulated 5 km race on a treadmill. VO2 during the running economy test was significantly higher at D11 of CT (52.5 +/- 1.5) compared to RT (51.1 +/- 1.4 ml.kg-1.min-1). RER, carbohydrate oxidation, and lactate were significantly lower; whereas, foot impact shock was significantly higher following both training modes. No significant changes in run performance, resting heart rate and blood pressure occurred during the study. In summary, 10 d of increased training resulted in a reduced running economy for CT, and a lower carbohydrate oxidation and an increase in foot impact shock for both training modes.

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