Building Up Muscle Strength

Happy Late October Evening,

I'm about 2 years post op from a SADi DS and have lost about 150lbs, down from 300lbs. I used to run a lot in my twenties and then nothing in my mid thirties to early fifties. I'm now 55 yrs old and have been walking and biking a lot for the past year. I run about a half mile as one of my laps walking around the park, but I seem to be having trouble building up enough leg muscle strength to run further distances without doing some damage. My legs appear very strong and I have a substantial amount of muscle on them given my new skinny size but it doesn't seem to matter for running. Biking is no issue. 

Has anyone else had this issue with running or know any ways to fix this?

I have had knee issues in the past but found out that building up my quads helped me with the knee issues. You are not saying what part of the legs are giving you issue or what kind of pain. There are many exercises out there to help build up the muscles for running. squats are good, lunges leg lifts with weights around the ankle just some ideas

It may not be a muscle issue at all, but joint issues from years of obesity.

You must focus on training specifically for endurance to help with your leg strength.  Simply put, for the purposes of this conversation, we have two main types of muscle fibers, slow twitch and fast twitch.  Fast twitch are your 'fight or flight' muscles that allow explosive movements.  These grow larger and at a more rapid rate than slow twitch.  Slow twitch muscle fibers are those that allow a longer time under tension and are typically found in the abs, legs and calves.  These can sustain a heavier volume of work inherently by the way they are trained (walking, standing upright, etc), otherwise we'd be falling all over ourselves 24/7!  That being said, you should focus on training your slow twitch muscle fibers accordingly to help maintain proper posture during exercise while keeping the amount of work volume high.  Supplementation and nutrition peri-workout is also key for this.  You can check out glutamine, chondroitin, MSM, glucosamine for the 'pain'.  I would also make sure I had sufficient carbohydrates in my system (the RIGHT ones at the RIGHT times) to further help fuel the workout.  Lastly, understand that you can absolutely train a specific muscle fiber properly.  It goes well beyond the standard weight lifting practices of "3 sets of 10", you have to train according to your goals.  So remember, high volume training and secondary isolation exercises for quads and hams are key to eliciting further Type II muscle fibers.  Feel free to message me for more info! Thanks and best of luck!

Thanks for all the feedback. It doesn't seem to be a joint issue but more like my tendons will give out if I don't stop running. I usually bike about 10 miles before I walk / run laps at the local park. I have substantial muscle development on my legs / thighs, but the tendons in my lower legs seem weak for what they should be. I take protein pills and supplements every day and generally get about 150 grams. I also lost enough weight that I'm not carrying any fat that would create a strain on my joints. 

The habits of your youth will dictate the problems of your old age.  Even if you don't have extra fat now, you DID, and the damage to your joints was done.  So I wouldn't discount joint trouble.  

I would recommend making an appointment with a physical therapist or orthopedist and getting checked out.  

Protein pills?  The efficacy and bioavailability of these post WLS have to be giving you a considerably under dosed total...You'd have to take dozens of them per day to initiate any type of protein synthesis response.  What type and mg are they?  Again, as for the muscular fatigue in the legs while running, I suggest building up your slow twitch muscle fibers first....try a leg workout twice per week outside of your cardio.  Focus on unilateral exercises, such as single leg leg curls and leg extensions, high volume squats and lunges.  Be sure to add in work for your abductors and adductors as well as calves and soleus.  These will allow a greater strength curve over time and will help build ALL of the muscles in the leg.  Remember, when you begin to fatigue, the most underdeveloped portion of the leg will go first (think of shin splints for example), so you want to make sure you're adhering to a program that hits the entire muscle properly, not just one specific portion (like people who focus on quads and don't do much for hamstrings...or people that do a bunch of standing and seated calf raises and neglect the soleus, or front portion of the lower leg).  You MUST work antagonistic muscle groups together!  Best of luck!  Keep us posted!