What’s going on in navasana (boat pose)?
There are few poses that elicit as much grumbling as navasana. Does anyone look forward to this pose? But, where there are challenges, there are also opportunities to learn and stretch ourselves. Navasana certainly provides us with those opportunities.
When we lift our legs up into navasana, iliacus and psoas major (or the iliopsoas) primarily create that action since they are the strongest hip flexors. The quadriceps and abdominal muscles are not the primary actors here. Instead, they function to support, rather than initiate, our primary action of lifting the legs.
The quadriceps muscles are working to straighten or extend the knee joint. They typically will fatigue quicker on those of us with tighter hamstrings. This is because it is hard for them to gain leverage with the legs in the air and because, the tighter the hamstrings are, the more resistance they create in this position (hip joint flexed).
The abdominals are working to stabilize the pelvis and torso relative to one another so that the iliopsoas can create the hip flexion. If your abdominals are your weaker point, then certainly the abdominal muscles will work harder. The weight of the legs and maintenance of the angle at the hip joint, create even more work for these muscles.
Resisting external rotation
One of the reasons that we might feel like we have to work so hard in this pose is that the iliopsoas is also an external rotator of the hips. So, we have to engage the iliopsoas to flex the hips, but then we also have to resist the external rotation by putting some intention into internally rotating the hips. We use both the adductors and the tensor fascia latae to do this action. The adductors work to keep the legs together, while the tensor fascia latae works to internally rotate the legs. You know this is working if you feel the cramp beginning just on the outside of the leg and near the hip joint.
We have seen parts of the action that we do in navasana before we get there in the primary series. Our actions in both legs in navasana are very similar to what the lifting leg is doing in the first part of utthita hasta padangusthasana. So, if we have really been working that pose, then the action of navasana should feel somewhat familiar, except now we have both legs up in the air at the same time.
Most postures fit into more than one category of postures. Few postures are just one thing. Besides the leg lifting action, navasana could also be considered a forward bend of essentially the same configuration as dandasana. Navasana is a forward bend that is tipped back 45°. You could also consider that navasana is a balancing posture in a way. Because, as with any balancing pose, one of the things that makes navasana a challenge is resisting gravity.
Techniques and challenges
Relax. Yes, really. If you aggressively go at this pose, it’s likely that your muscles will fatigue before you finish the five repetitions that we typically do in the Ashtanga system. It’s also likely that one or more of the hip stabilizing muscles (TFL, gluteus minimus, gluteus medius) will start to cramp. Use as little strength as possible, but as much as necessary.
Cultivate at least moderate flexibility in the hamstrings. If tight hamstrings are pulling your pelvis under in a posterior tilt when you try to sit up in dandasana, then it will likely also feel challenging to sit up in navasana. Hamstring tension is related to a somewhat common suggestion in this pose, which is, in navasana you should only be on your sit bones. This is a great ideal to work toward, there is no question about it. The problem is, that it is very difficult to do.
Many students struggle with tight hamstrings. If the hamstrings are tight, they are going to pull your pelvis under in what we call a posterior tilt. When that happens, you’re more likely to be not just on your sit bones, but also on your sacrum and/or tailbone. The most common reason that when we bend our knees we are able to sit upright more easily, is that we have reduced the hamstring tension and have more contact with the sit bones directly.
Modifications while cultivating strength in navasana
There are many options for working in navasana in a way that builds strength, without overdoing it. If keeping the legs up in the air feels impossible, you can hold the sides of the legs until you get strong enough to keep the legs up without the extra boost. Alternately, you can also hold the side of just one leg and keep the other leg working without the extra support. Then, on your next repetition of navasana, switch the side that you are holding the leg on. Another option, as you are building strength in this pose, is to place yourself where you can just barely reach your toes to a wall. This will give you a little support from the wall, but will also require you to put forth most of the effort to keep the legs up.