Very interesting study below from Dr. Kraemer and friends. Once again, it shows that animal studies tend to not match human studies, but those little critters are so much easier to study than humans!
While this study shows that testosterone did NOT change, this only applies to the specific exercise they used and was an acute study, so it did NOT look at any changes in protein synthesis (building muscle). We know from many other studies that lifting weights helps build muscle and strength, but the exact mechanism is pretty complicated.
Effect of Resistance Exercise on Muscle Steroidogenesis.
Vingren JL, Kraemer WJ, Hatfield DL, Anderson JM, Volek JS, Ratamess NA, Thomas GA, Ho JY, Fragala MS, Maresh CM.
J Appl Physiol. 2008 Oct 2. [Epub ahead of print]
University of Connecticut. Circulating testosterone is elevated acutely following resistance exercise (RE) and is an important anabolic hormone for muscle adaptations to resistance training. The purpose of this study was to examine the acute effect of heavy RE on intracrine muscle testosterone production in young resistance trained men and women. 15 young highly resistance trained men (n=8; 21+/-1 years, 175.3+/-6.7 cm, 90.8+/-11.6 kg) and women (n=7; 24+/-5 years, 164.6+/-6.7 cm, 76.4+/-15.6 kg) completed 6 sets of 10 repetitions of Smith's machine squats with 80% of their 1-repetition maximum. Before RE, and 10 min and 70 min after RE, muscle biopsies were obtained from the vastus lateralis.
Before RE, after 3 and 6 sets of squats, and 5, 15, 30 and 70 min into recovery from RE blood samples were obtained using venipuncture from an anticubital vein. Muscle samples were analyzed for testosterone, 17beta-hydroxysteroid dehydrogenase (HSD) type 3, and 3beta-HSD type 1-2 content. Blood samples were analyzed for the glucose and lactate concentrations. No changes were found for muscle testosterone, 3beta-HSD1-2, and 17beta-HSD3 concentrations. However, a change in protein migration in the Bis-Tris gel was observed for 17beta-HSD3 post-exercise; this change in migration indicated ~2.8 kd increase in molecular weight.
Conclusion: These findings indicate that species differences in muscle testosterone production may exist between rats and humans.
In humans, muscle testosterone concentrations do not appear to be affected by Resistance Exercise. This study expands on the current knowledge obtained from animal studies by examining resting and post-exercise concentrations of muscle testosterone and steroidogenic enzymes in humans.
"Only in the absence of certainty can we have open-mindedness, mental flexibility and willingness to contemplate alternative ideas."
---Robert Burton from "The Certainty Bias"
Charles Staley's Training Summit
I am off to Charles Staley's Training Summit this weekend. It will be a short trip as I fly out Friday evening and then back on Monday. I am excited about seeing some people that I have not seen in a long time. I will be crashing in a room with Dave Barr, so that will be a trip! Be sure to check out his products the Anabolic Index books HERE (I get no money for any sales of his books and I do recommend them as I have both).
Charles Staley's Training Summit
Sunday, October 18 &19th, 2008
If you are going to be there, please come up and say hi to me! I still need to find a place to crash on Sunday night, but I am sure something will work out.
The agenda (which may change at our discretion) is as follows:
Day 1 Oct 18th
8:00 AM Charles Staley
10:30 AM Phil Stevens
11:45 AM Lunch
1:00 PM Cassandra Forsythe
2:15 PM Robert Fortney
3:30 PM David Barr
4:45 PM Christopher Drummond
6:00 PM Optional Dinner
Day 2 Oct 19th
7:00 AM Dr. Lonnie Lowery
8:15 AM Tim Larkin
9:30 AM Luiz Da Silva
10:45 AM Lunch
12:00 PM Joe Micela
1:15 PM Anthony Almada
2:15 PM Joe Marsit
3:30 PM Q and A Roundtable
It will be a blast and I am looking forward to it. I will provide updates most likely once I return, so stay tuned!