Acute Cardiorespiratory and Metabolic Effects of a Sandbag Resistance Exercise Protocol.

The purpose of this study was to examine the acute cardiorespiratory and metabolic effects of a sandbag (SB) resistance exercise protocol and compare the responses to time-matched treadmill running protocols. Eight healthy, resistance-trained men (21.1 +/- 1.0 years; 86.1 +/- 7.8 kg) completed 4 protocols of equal duration in random sequence: (a) SB, (b) treadmill running at 60% of (V) over doto(2) reserve (60(V) over doto(2)R), (c) treadmill running at 80% of (V) over doto(2) reserve (80(V) over doto(2)R), and (d) a control protocol. The SB protocol was 16 minutes in duration and consisted of 3 circuits of 8 multiple-joint exercises (with 11-, 20-, or 48-kg SBs) performed for as many repetitions as possible for 20 seconds followed by a 10-second rest interval before beginning the next exercise. Two minutes of rest was allowed between circuits. Breath-by-breath oxygen consumption ((V) over doto(2)) and heart rate (HR) were recorded throughout each protocol and for 30 minutes postexercise (PE) and blood lactate was determined before and immediately after each protocol. Blood lactate was significantly higher after SB compared with 60(V) over doto(2)R and 80(V) over doto(2)R. Mean and peak HR in SB was significantly higher than 60(V) over doto(2)R but not different from 80(V) over doto(2)R. Mean (V) over doto(2) and energy expenditure (EE) in SB was significantly lower than 60(V) over doto(2)R and 80(V) over doto(2)R during each protocol but significantly higher after SB compared with 60(V) over doto(2)R and 80(V) over doto(2)R PE. Compared with 60(V) over doto(2)R and 80(V) over doto(2)R, respiratory exchange ratio was significantly higher during SB and through 5 minutes PE, but was significantly lower at 2530 minutes PE after SB. Sandbag, as performed in this study, provides a superior metabolic stimulus to treadmill running during the PE period; however, the SB results demon strate inferior EE compared with running at 60(V) over doto(2)R and 80(V) over doto(2)R.