Triathlon.

From its roots in San Diego to its Olympic debut in Sydney in 2000, triathlon has emerged as a popular sport with a wide variety of participants. Because of the nature of the sport, excessive training resulting in overuse injuries is common. Triathlon injuries can also be unique from the individual sports involved in that they are attributed to a cumulative effect of multi-sport training. Because many triathletes have not grown up participating in the individual sports, biomechanics in each of the disciplines must also be considered as a source of injury. Nutrition and environmental factors and the role that they play in the endurance athlete should also not be overlooked. The sport of triathlon is rapidly growing, and the ability to recognize the unique aspects of these injuries can help the multisport athlete to train properly and be healthier and more successful.

Median and ulnar antidromic sensory studies to the fourth digit.

The literature documents multiple reports of neurological injury resulting from both the implantation and the removal of orthopedic devices. These injuries can be easily and objectively evaluated with nerve conduction studies. This study was undertaken to derive a normative database for median and ulnar sensory conduction studies to the fourth digit. Testing was done utilizing a 14-cm antidromic technique on 192 asymptomatic subjects with no risk factors for neuropathy. The subjects were studied bilaterally. Onset latency, peak latency, onset-to-peak amplitude, peak-to-peak amplitude, rise time, and duration were recorded. Increasing age and body mass index were associated with decreasing amplitudes and area. No other demographic factors correlated with differences in waveform measurements. Mean onset latency was 2.7 +/- 0.3 ms for the median nerve and 2.6 +/- 0.2 for the ulnar nerve. Mean peak latency was 3.4 +/- 0.3 ms for the median nerve and 3.3 +/- 0.3 ms for the ulnar nerve. Mean onset-to-peak amplitude was 21 +/- 12 muV for the median nerve and 23 +/- 12muV for the ulnar nerve. Mean peak-to-peak amplitude was 34 +/- 20 muV for the median nerve and 36 +/- 23 muV for the ulnar nerve. Mean area was 25 +/- 17 nVs for the median nerve and 28 +/- 19 nVs for the ulnar nerve. Mean rise time was 0.7 +/- 0.1 ms for the median nerve and 0.7 +/- 0.2 ms for the ulnar nerve. Mean duration was 1.9 +/- 0.4 ms for the median nerve and 1.9 +/- 0.5 ms for the ulnar nerve. The mean difference in onset and peak latency between the median and ulnar nerves (median minus ulnar) was 0.1 +/- 0.2 ms. The upper limit of normal difference of median greater than ulnar onset and peak latency was 0.5 ms. The upper limit of normal difference of ulnar greater than median onset latency was 0.2 ms (0.3 ms for peak latency). The upper limit of normal drop in median peak-to-peak amplitude from one side to the other was 56%. For the ulnar nerve this value was 73%.

Comparison of median and radial sensory studies to the thumb.

There are multiple reports of neurological injury from both the implantation and the removal of devices utilized in orthopedics. Nerve conduction studies can be a valuable tool in evaluating the acuity, severity, and prognosis of these injuries, as well as in tracking their course. This study was undertaken in an effort to create a large normative database for examining median and radial sensory nerve conduction studies to the first digit. An antidromic technique was employed utilizing a 10-cm distance between the stimulating and recording electrodes. Two hundred three asymptomatic volunteers were tested. Onset latency, peak latency, onset-to-peak amplitude, peak-to-peak amplitude, area, rise time, and duration of the waveforms were measured. Males, older subjects, and those with higher body mass index (BMI) were found to have lower amplitude and area on the median nerve studies. Age was the only variable which demonstrated significant correlation with differing results on the radial nerve studies. Mean onset latencies were 2.1 +/- 0.2 ms for the median nerve and 2.0 +/- 0.2 ms for the radial nerve. Mean peak latencies were 2.7 +/- 0.2 ms for the median nerve and 2.6 +/- 0.2 ms for the radial nerve. Mean peak-to-peak amplitude for the median nerve was 45 +/- 24 muV and for the radial nerve was 12 +/- 9 muV. The upper limit of normal difference in median-versus-radial onset latency was 0.5 ms (0.6 ms for peak latency). The upper limit of normal difference in radial-minus-median onset latency was 0.3 ms (0.4 ms for peak latency).