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Forearm Blood Flow Regulation Following Maximal Strength Training-induced Improvements in Work Efficiency: 279 Board #100 May 31 1100 AM - 1230 PM

Berg, Ole Kristian1; Nyberg, Stian K.2; Windedal, Tobias M.2; Wang, Eivind2

Medicine & Science in Sports & Exercise: May 2017 - Volume 49 - Issue 5S - p 60
doi: 10.1249/01.mss.0000516989.54129.16
A-44 Free Communication/Poster - Cardiovascular Responses to Exercise Wednesday, May 31, 2017, 7:30 AM - 12:30 PM Room: Hall F
Free

1Molde University College, Molde, Norway. 2Norwegian University of Science and Technology, Trondheim, Norway.

(No relationships reported)

Maximal strength training (MST) improves submaximal work efficiency (WE) in the arms. However, since assessment of muscle oxygen uptake (V[Combining Dot Above]O2) during exercise is lacking, the behavior of MST-induced adaptations is unknown, and it remains elusive if metabolic and vascular responses in arms may contrast what has been observed in legs.

PURPOUSE: To investigate responses in arm blood flow and arteriovenous oxygen difference (a-vO2diff) during steady state exercise following MST.

METHODS: Thus, utilizing Doppler-ultrasound and a catheter placed in the subclavian vein for measurements of blood flow and a-vO2diff, we assessed steady state WE and peak responses in seven young males (24±2(SD) years) following a six-week handgrip MST intervention.

RESULTS: As expected, MST improved maximal strength (49±9 to 62±10kg) and rate of force development (923±224 to 1086±238N·s−1), resulting in a reduced submaximal V[Combining Dot Above]O2 (31±9 to 25±10mL·min−1) and concomitantly increased WE (8.8±2.3 to 11.7±3.6%) (all p<0.05). In turn, the WE-improvement led to a reduced blood flow (486±102 to 395±114mL·min−1), mediated by a lower heart rate (66±4 to 59±7beats·min−1) and blood velocity (43±8 to 32±6cm·s−1) (all p<0.05). Conduit artery diameter and a-vO2diff remained unaltered. The peak test revealed increased time to exhaustion (948 to 1104 seconds; p<0.05), and a tendency towards increased peak work rate (p=0.06), but no change in peak oxygen uptake.

CONCLUSION: Despite arguments of metabolic and vascular limb-specific differences, these results reveal that the mechanisms responsible for WE adaptations following small muscle mass MST in the upper extremities is a direct reflection of what has been documented for lower extremities. Additionally, our data show that the advantageous reductions in blood flow is regulated through conduit artery blood velocity.

© 2017 American College of Sports Medicine