Over the past year I have been using the O2 sensor for weight training, in both low load and conventional style routines. I have skipped a warmup set, since it seemed a waste of time for whatever benefit it could provide. However, after appreciating the reasonable desaturation a low load set can can provide, I decided to try incorporating occasional warmups in my routine. The rational was based on the observation that the first set provides the best chance to desaturate the muscle using a very low load (before vasodilitation occurs). In a previous post, the reverse drop set was used to compensate for this hyperemia by progressively boosting the load lifted to induce more muscle external compression. So what do the tracings look like if a warmup set is done at the same resistance as the low load? Does this impact desaturation on the next set?
This is a tracing of the O2 saturation and total Hb with the sensor on the lats, doing a pulldown. Initial weight was exactly what I do for a 45-60 sec low load, the second set was a 10 RM load.
As noted, the warm up produces a non trivial desaturation in the 15% range as well as a drop in total Hb (external compression). Of course, it is significantly less than the conventional load. Also of interest is the total Hb pattern:
Compare the up and down spikes during the warmup to the constant drop of a heavier load. The warmup/low load just can't compress the muscle as well and I suspect that at certain points during the range of motion (or eccentric phase) there is blood flowing in.
Now, there may be other locations where the particular machine/exercise will not target a given muscle well("non targeted area") and the sensor will not pick up much change.
Here is the same sensor location as above(lats), but doing a row, first a warmup then 10 RM:
The desaturation is minimal, and the total Hb drop is not really seen in this particular location during the warmup. However, at the 10 RM load both take place quite well.
However, if the sensor was moved a bit, the row and pulldown patterns could reverse (with the row looking better on the warmup).
I think the bottom line here is the following:
If you have the time, a warmup set in the realm of a "low load" performed for 45 seconds can produce reasonable desaturation in certain parts of the muscle that are best targeted by that particular exercise motion. However, the degree of O2 drop is nowhere near what conventional loads can do and the "overlap" to other muscle groups that are not primary targets is much better.
Another example, this is a "posterior deltoid" machine with the sensor on the lats. This exercise typically targets the posterior part of the deltoid and very little weight is needed to cause a desat at this location. However, what happens if the sensor is placed on the lats (not the target) for both the warm up and a 10 RM set? Unfortunately not much!
As seen above, the non targeted muscle gets great desaturation with the heavier weight. So for this muscle group, the warmup is not going to add that much more effect. However, if we looked at the posterior deltoid, the low load warmup would have been more significant.
- A warmup set of a low load will generally produce a reasonable desaturation in the main targeted muscles.
- The additive anabolic stimulus should be helpful over the long term
- However the low load will not effect non-targeted areas as well.
- Because of the above, if conventional strength training can be done (no injury), it is probably a good idea to do so on a regular basis and not rely exclusively on low load training. More areas can be targeted by the conventional load technique.