ACTN3 "Sports Gene" genotype results

[Lipitzan]

This particular gene is responsible for the activation or deactivation of a fast twitch muscle protein called Actinin. The double RR allele is overrepresented among Olympic sprinters and power lifters, as the RR double allele is associated with an increase in fast twitch muscle fiber which is crucial for explosive muscle movements. The double knockout or "XX" type is associated with superior endurance. The slow twitch muscle dominant XX type utilizes oxygen more efficiently in the muscles and apparently has a higher VO2Max response to excercise. The RX allele, with one activating and one deactivating allele, is associated with intermediate explosive muscle capabilities and also has been found to be more associated for endurance than than the RR type.

I show up as having the XX double allele, which is associated more with endurance, which was surprising. I was on the football team in high school and a boxer in high school and college, and I always thought I was an explosive type. At the same time, ive always been quite thin at around 157 Ibs while most of the men in my family tend to be well over 200 Ibs. So now I've decided to try adjusting my workout to see if I notice a difference in training results, focusing more on cardio than sprint or weight training.

Anyone else take this test and want to share their results? Are you a weightlifting type of person, cardio, athletic? Non athletic? Are you more of a mesomorph or ectomorph?

[Couscous Nomad]

Rs1815739 TT
Impaired muscle performance. Likely endurance athlete.

http://www.snpedia.com/index.php/Rs1815739

[poorejj]

ACTN3 "Sports Gene" genotype results

I know it has been several months since you posted this question, but I have just now seen it... I am also very interested in this. I have recently (at the beginning of 2014) taken a YDNA, MtDNA, and autosomal DNA test and then I used the raw autosomal results with promethease to find out I had the ACTN3 mixed type, or RX... I was really hoping that I would have been RR, but unfortunately I am not. However, it does make sense, because when I was in advanced weight training classes in high school, I was far from the weakest kid, but I was also not the strongest... You could tell a difference in muscular endurance in different kids too. For instance, I was good at lifting moderately heavy weight for moderate reps and fairly high number of sets, while the really big guys would only do 1 to 3 reps very explosively, but would only go for 1 to 3 sets. I never felt like that low of set/rep range greatly benefited me, but I had awesome gains with the 5x5 routine.... Furthermore, there were those really skinny guys that could never put on any weight, but they were like energizer bunnies and kept going and going. They could take a light to moderate weight and just rep it over and over and over, and with just a short break, they could come back and do it again! I think the best way to spot one of those endurance guys is pushups. Those guys can always do an unbelievable number of pushups, as long as they are not fat couch potatoes, but regularly exercise... S

[Martin]

XX too

I have also taken this test, and I have found out that I am XX as well. This was also surprising to me. I am a 52 years old man, who always liked the sprint running in track and fields. I run 60 meter indoors with relatively good results. When trying to run long distance or cross country skiing, I may have some endurance, but most people seem better than me in the long run anyway. The same goes for archery, where I can sometimes excel in 15 arrows, before muscle fatigue, but never in 60 arrows.
When i used to participate in 5 km running events when I was younger, then I always wondered where the others were after 500 meter or 1 km, but after 2 or 3 km, they always kept coming from behind.
But probably the test is correct. I tried dumbbell biceps curl with 80% of RM. Then >12 repetitions should indicate slow twitch muscles and <7 repetitions should indicate fast twitch muscles. I did 12 repetitions quite easily, but soon I was totally stopped by fatigue.

[Martin]

XX but not excelling in pushups

I think the best way to spot one of those endurance guys is pushups. Those guys can always do an unbelievable number of pushups, as long as they are not fat couch potatoes, but regularly exercise... S

I also made the same observation, but I could never excel at pushups. I am now a 52 years old man, 77 kg, and fatigue stops me after 20 pushups.
Still the ACTN3 test showed that I am XX as well. I have never had the feeling of having fantastic endurance. Sooner or later the fatigue comes.
The only sport where I could excel has been 60 meter sprint running. That seems contradictory, I think.