There are plenty of products out there that purport to increase blood flow to the muscle, and thereby to increase strength and size. However, for those who have dared to crack the spine on a physiology (or kinesiology or biology) textbook, you’ll note that nowhere in any of the scientific literature does it mention that increasing blood flow (per se) leads to increased strength or size.
According to Dr. Vladimir Zatsiorsky, overall muscle growth is caused by a combination of sarcoplasmic hypertrophy and myofibrillar hypertrophy. The first mechanism is an increase in the sarcoplasm. Although the sarcoplasm is located within the muscle cell itself, it doesn’t actually contribute to force production. This is the “bigger but not stronger” phenomenon we see with a lot of bodybuilders, generally achieved with a higher repetition scheme. The dude that came in second place at the Mr. Olympia this year is one of those guys who preaches the advantages of this methodology, along with various other notable bodybuilders (Milos Sarcev comes to mind).
The other way to increase muscle growth is myofibrillar hypertrophy – this is the one that contributes to force production (because myofibrils are contractile tissue, while in contrast, the sarcoplasm is simply the fluid in the cell itself).
However, although there are two potential ways to get bigger, there is only one way to get stronger. The increase in sarcoplasmic fluid tends to accompany higher rep training, as does an increase in blood flow to the area, but while the training itself can rightly be seen as the cause for eventual growth, the increase in blood flow is not thought to be a contributory factor.
Also, let’s not forget that so-called Occlusion Training, where blood flow is actually restricted, has been shown to increase hypertrophy to a greater extent (given specific parameters) than traditional resistance training.
Still, we find that increased blood flow can be highly correlated to an increase in muscle size and perhaps strength. So what product has been proven to actually increase blood flow? Regular old Creatine monohydrate (study below – you can just skip to the underlined part at the end). Creatine is cheap, safe, and effective. It’s one of the few nutritional supplements that has been extensively studied for decades, with a very low percentage of non-responders and a very high percentage of people realizing vastly improved gains in strength both strength and fat free mass.
Here’s the study:
Metabolism. 2001 Dec;50(12):1429-34.
Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow.
Arciero PJ, Hannibal NS 3rd, Nindl BC, Gentile CL, Hamed J, Vukovich MD.
Exercise Science Department, Skidmore College, Saratoga Springs, NY, USA.
This study determined the effects of 28 days of oral creatine ingestion (days 1 to 5 = 20g/d; [5 g 4 times daily]: days 6 to 28 = 10 g/d; [5 g twice daily]) alone and with resistance training (5 hours/week) on resting metabolic rate (RMR), body composition, muscular strength (1RM), and limb blood flow (LBF). Using a double-blind, placebo-controlled design, 30 healthy male volunteers (21 +/- 3 years; 18 to 30 years) were randomly assigned to 1 of 3 groups; pure creatine monohydrate alone (Cr; n = 10), creatine plus resistance training (Cr-RT; n = 10), or placebo plus resistance training (P-RT; n = 10). Body composition (DEXA, Lunar DPX-IQ), body mass, bench, and leg press 1RM (isotonic), RMR (indirect calorimetry; ventilated hood), and forearm and calf LBF (venous occlusive plethysmography) were obtained on all 30 subjects on 3 occasions beginning at approximately 6:00 AM following an overnight fast and 24 hours removed from the last training session; baseline (day 0), and 7 days and 29 days following the interventions. No differences existed among groups at baseline for any of the variables measured. Following the 28-day interventions, body mass (Cr, 73.9 +/- 11.5 v 75.6 +/- 12.5 kg; Cr-RT, 78.8 +/- 6.7 v 80.8 +/- 6.8 kg; P <.01) and total body water (Cr, 40.4 +/- 6.8 v 42.6 +/- 7.2 L, 5.5%; Cr-RT, 40.6 +/- 2.4 v 42.3 +/- 2.2 L, 4.3%; P <.01) increased significantly in Cr and Cr-RT, but remained unchanged in P-RT, whereas, fat-free mass (FFM) increased significantly in Cr-RT (63 +/- 2.8 v 64.7 +/- 3.6 kg; P <.01) and showed a tendency to increase in Cr (58.1 +/- 8.1 v 59 +/- 8.8 kg; P =.07). Following the 28-day period, all groups significantly increased (P <.01) bench (Cr, 77.3 +/- 4 v 83.2 +/- 3.6 kg; Cr-RT, 76.8 +/- 4.5 v 90.5 +/- 4.5 kg; P-RT, 76.0 +/- 3.4 v 85.5 +/- 3.2 kg), and leg press (Cr, 205.5 +/- 14.5 v 238.6 +/- 13.2 kg; Cr-RT, 167.7 +/- 13.2 v 238.6 +/- 17.3 kg; P-RT, 200.5 +/- 9.5 v 255 +/- 13.2 kg) 1RM muscular strength. However, Cr-RT improved significantly more (P <.05) on the leg press 1RM than Cr and P-RT and the bench press 1RM than Cr (P <.01). Calf (30%) and forearm (38%) LBF increased significantly (P <.05) in the Cr-RT, but remained unchanged in the Cr and P-RT groups following the supplementation period. RMR expressed on an absolute basis was increased in the Cr (1,860.1 +/- 164.9 v 1,907 +/- 173.4 kcal/d, 2.5%; P <.05) and Cr-RT (1,971.4 +/- 171.8 v 2,085.7 +/- 183.6 kcal/d, 5%; P <.05), but remained unchanged from baseline in P-RT. Total cholesterol decreased significantly in Cr-RT (-9.9%; 172 +/- 27 v 155 +/- 26 mg/dL; P <.01) compared with Cr (174 +/- 46 v 178 +/- 43 mg/dL) and P-RT (162 +/- 32 v 161 +/- 36 mg/dL) following the 28-day intervention. These findings suggest that the addition of creatine supplementation to resistance training significantly increases total and fat-free body mass, muscular strength, peripheral blood flow, and resting energy expenditure and improves blood cholesterol.