I will include as much technical detail as possible in hope of getting useful suggestions.
background: I've been running barefoot for over 4 years, have never worn minimalist shoes, weigh 180 pounds but am fast. I focus on short middle distance and never race above 5k. During summer training I've altered my form by adjusting my center of mass forward a bit.
onset: after a 3k run at lactate threshold, I felt a focused pain in my right foot centered under the 2nd and 1st metatarsal shafts, interfering with and weakening push-off. This subsided after about 5 minutes of walking and remained a dull but annoying ache during about 2k of cool-down jogging.
persistence: rested for 4 days. During this time, pain occurred when standing up, centered around the 2nd metatarsal. It was sharp at times but did not feel like a SF, more like an acute tear to soft tissue. It seemed to migrate around to the inter-metatarsal spaces, to the lower muscles and fascia (FDB and FHB), to ordinary TOFP, and forward to under the 2nd metatarsal head. I supposed that inflammation was occurring.
This pain was not severe but was annoying enough to affect my gait when initially standing and walking. It did not improve over the 4 days, however it was no hindrance at all to walking, jumping, or other athletic movements and tended to decrease rather than increase when bearing weight.
strangeness: So after 4 days, I decided to try a bit of jogging, found it completely painless, and proceeded with a light workout, including a few intervals at 800m race pace in spikes. The pain, when it existed, was a barely noticeable dull ache around the 2nd to 3rd metatarsals. When running it seemed focused under the 2nd metatarsal head and, near the end of the workout, in the distal 2nd phalange. I don't have Morton's toe, but my right 2nd phalanges have gotten sore before, often feeling like they've been stubbed after a fast run. My right ankle is relatively loose from a sprain about 20 years ago and may contribute to biomechanical issues. I've also got a bit of soreness and tightness in my hip flexors, medial glutes and the fascia around my right femur which preceded this by a few days.
Since it hurts only when I'm not running, I'm fairly convinced that I haven't got a MSF, but I'm still scratching my head over this. Other than a generic overuse injury, I have no idea what it might be.
background: I've been running barefoot for over 4 years, have never worn minimalist shoes, weigh 180 pounds but am fast. I focus on short middle distance and never race above 5k. During summer training I've altered my form by adjusting my center of mass forward a bit.
onset: after a 3k run at lactate threshold, I felt a focused pain in my right foot centered under the 2nd and 1st metatarsal shafts, interfering with and weakening push-off. This subsided after about 5 minutes of walking and remained a dull but annoying ache during about 2k of cool-down jogging.
persistence: rested for 4 days. During this time, pain occurred when standing up, centered around the 2nd metatarsal. It was sharp at times but did not feel like a SF, more like an acute tear to soft tissue. It seemed to migrate around to the inter-metatarsal spaces, to the lower muscles and fascia (FDB and FHB), to ordinary TOFP, and forward to under the 2nd metatarsal head. I supposed that inflammation was occurring.
This pain was not severe but was annoying enough to affect my gait when initially standing and walking. It did not improve over the 4 days, however it was no hindrance at all to walking, jumping, or other athletic movements and tended to decrease rather than increase when bearing weight.
strangeness: So after 4 days, I decided to try a bit of jogging, found it completely painless, and proceeded with a light workout, including a few intervals at 800m race pace in spikes. The pain, when it existed, was a barely noticeable dull ache around the 2nd to 3rd metatarsals. When running it seemed focused under the 2nd metatarsal head and, near the end of the workout, in the distal 2nd phalange. I don't have Morton's toe, but my right 2nd phalanges have gotten sore before, often feeling like they've been stubbed after a fast run. My right ankle is relatively loose from a sprain about 20 years ago and may contribute to biomechanical issues. I've also got a bit of soreness and tightness in my hip flexors, medial glutes and the fascia around my right femur which preceded this by a few days.
Since it hurts only when I'm not running, I'm fairly convinced that I haven't got a MSF, but I'm still scratching my head over this. Other than a generic overuse injury, I have no idea what it might be.