Tuesday, March 22, 2011

Can you overtrain the bone in a height increase program?

We know that there are several components to the mechanosensativity of the bone and the cells within the bone.  It's important to note that the mechanical sensitivity of the osteogenic bone cells is important as they upregulate TGF-Beta1 which is vital to induce chondrogenic differentiation.  The multiple factors that can affect the mechanosensativity of the relevant cells which include mesenchymal stem cells, chondrocytes, and osteoblasts are:  actin dynamics(actin depolymerisation), neuronal regulation(CGRP and ACTH concentrations), and ion channels(Ca+ which is influenced by CGRP and ACTH, the ion channels may deregulate to lower mechanosensativity).

There are three common modalities of overtraining in muscular performance:

1) Neurological Fatigue.  Caused by lifting very heavy weights.  Your muscles may be fine but your neurons can not properly fire to contract the muscle.

2) Structural Fatigue:  Muscular damage.  There's too much muscular fiber damage for the body to lift the weight.  Your CNS fires for the muscle to lift but nothing happens.

3) Metabolic Fatigue:  Your muscles don't have enough energy.  Glycogen, ATP, Oxygen, etc. levels are too low.  Structurally the muscle can contract and neurologically the synapses can send the signals but there's not enough energy for the muscle to move.

All three of these modalities have to be properly functioning for the muscle to move.  Metabolic Fatigue is the easiest to recover from with recovery being in possible seconds, followed by structural fatigue, and finally neurological fatigue which is the hardest to recover from.

Now in LSJL you are not contracting the bone.  The clamp is providing the stimulus on the bone but there can still be neurological failure.  The neurons involved in inducing chondrogenic differentiation can not fire.  ACTH and CGRP can be too low and need to recover.  Increasing ACTH and CGRP concentrations may help but the only solution to neurological overtraining is rest.

Structural fatigue is not likely to happen in bone for LSJL.  There could be microfractures that may prevent mechanical signaling but since LSJL doesn't involve contracting Type I collagen fibers structural fatigue should be a minor or non-existent issue.

Now metabolic fatigue could play a larger role especially with calcium.  It may be a problem with the voltage gate channels rather than being a problem with low calcium concentration which is easier to fix.  If it is a problem with the voltage gate channels then the most likely solution is rest to give the body time to repair and build new channels.  Barium has the ability to help with the voltage calcium gate channels.  A high barium concentration results in calcium voltage gate closure.  And a refractory period is needed between each pulse.  So unless, you can get blood work done and measure proper barium concentration taking barium as a supplement is not advised at this time.

So aside from possible supplementation options with ACTH, CGRP(which is not available), and Barium the best solution to bone overtraining is rest.

With muscular routines, it's easy to detect overtraining systems as it usually at a global level.  However, we are only training some limb limbs so the overtraining may be harder to detect especially since it's only within the CGRP and ACTH systems.

But, if you are feeling nerve pain then you are likely clamping too hard.  You should be progressively increasing the intensity and duration of clamping to give the body time to adapt and to encourage more adaptations at each stage of increase rather than having large increases in intensity right away.  An increase in load is needed to sufficiently disrupt the actin cytoskeleton to allow for chondrogenesisCH Turner stated that bone needed 24 hours to regain 98% of it's mechanosensativity.  It's unknown whether there's some sort of longitudinal reduction in mechanosensativity to repeated bouts of the same load over time or whether there's a gradual decrease in mechanosensativity over time(for example: the first 24 hours may result in a 98% gain in mechanosensativity whereas the next 24 hours may only result in a 96% gain).  The LSJL scientists performed LSJL on the rats 5 of 7 days a week with the 2 days of rest being non-consecutive.

Here's a paper that provides a model of bone mechanosensativity(osteocyctes and osteoblasts only but that's necessary for TGF-Beta1 and there's probably similarities between osteoblast mechanosensativity and mesenchymal stem cells):

Modeling of biological doses and mechanical effects on bone transduction.

"Shear stress, hormones like parathyroid and mineral elements like calcium mediate the amplitude of stimulus signal[These signals also affect height growth in addition to bone remodeling], which affects the rate of bone remodeling. The current study investigates the theoretical effects of different metabolic doses in stimulus signal level on bone. The model was built considering the osteocyte as the sensing center[no osteocytes in the epiphysis as there is only trabecular bone, but osteocyte signaling in cortical bone close to the epiphysis may be important for the TGF-Beta1] mediated by coupled mechanical shear stress and some biological factors. [Our model] describes the effects of physiological doses variations of calcium, parathyroid hormone, nitric oxide and prostaglandin E2 on the stimulus level sensed by osteocytes in response to applied shear stress generated by interstitial fluid flow. We retained the metabolic factors (parathyroid hormone, nitric oxide and prostaglandin E2) as parameters of bone cell mechanosensitivity because stimulation/inhibition of induced pathways stimulates osteogenic response in vivo."

The scientists state that the strength of the mechanical stimulus is strongly dependent on PGE2 and Nitric Oxide.  A higher fluid viscosity(more shear stress and likely hydrostatic pressure) also increases the strength of results. Shear stress stimulates the NO pathway so there is a connection there.  Damage to the bone canliculus actually made lower levels of shear strain more effective.  So structural damage to the bone is not likely to play a role in overtraining and structural damage to the bone may be beneficial in inducing adaptations. 

Neurological fatigue in bone is not well quantified.  To help prevent neurological fatigue:  Rest from LSJL 2 out of 7 non-consecutive week days and try to avoid using pressure that causes nerve pain.  If bone length stops increasing, take 2 weeks off from LSJL.

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