John C. Hill

Medical Services at Ultra-Endurance Foot Races in Remote Environments: Medical Issues and Consensus Guidelines

An increasing participation in ultra-endurance foot races is cause for greater need to ensure the presence of appropriate medical care at these events. Unique medical challenges result from the extreme physical demands these events place on participants, the often remote settings spanning broad geographical areas, and the potential for extremes in weather conditions and various environmental hazards. Medical issues in these events can adversely affect race performance, and there is the potential for the presentation of life-threatening issues such as exercise-associated hyponatremia, severe altitude illnesses, and major trauma from falls or animal attacks. Organization of a medical support system for ultra-endurance foot races starts with a determination of the level of medical support that is appropriate and feasible for the event. Once that is defined, various legal considerations and organizational issues must be addressed, and medical guidelines and protocols should be developed. While there is no specific or universal standard of medical care for ultra-endurance foot races since a variety of factors determine the level and type of medical services that are appropriate and feasible, the minimum level of services that each event should have in place is a plan for emergency transport of injured or ill participants, pacers, spectators and event personnel to local medical facilities.

Review and role of plyometrics and core rehabilitation in competitive sport.

Core stability and plyometric training have become common elements of training programs in competitive athletes. Core stability allows stabilization of the spine and trunk of the body in order to allow maximal translation of force to the extremities. Plyometric training is more dynamic and involves explosive-strength training. Integration of these exercises theoretically begins with core stabilization using more static exercises, allowing safe and effective transition to plyometric exercises. Both core strengthening and plyometric training have demonstrated mixed but generally positive results on injury prevention rehabilitation of certain types of injuries. Improvement in performance compared to other types of exercise is unclear at this time. This article discusses the theory and strategy behind core stability and plyometric training; reviews the literature on injury prevention, rehabilitation of injury, and performance enhancement with these modalities; and discusses the evaluation and rehabilitation of core stability.

Validation of Musculoskeletal Ultrasound to Assess and Quantify Muscle Glycogen Content. A Novel Approach

Abstract Glycogen storage is essential for exercise performance. The ability to assess muscle glycogen levels should be an important advantage for performance. However, skeletal muscle glycogen assessment has only been available and validated through muscle biopsy. We have developed a new methodology using high-frequency ultrasound to assess skeletal muscle glycogen content in a rapid, portable, and noninvasive way using MuscleSound (MuscleSound, LCC, Denver, CO) technology. Purpose: To validate the utilization of high-frequency musculoskeletal ultrasound for muscle glycogen assessment and correlate it with histochemical glycogen quantification through muscle biopsy. Methods: Twenty-two male competitive cyclists (categories: Pro, 1–4; average height, 183.7 ± 4.9 cm; average weight, 76.8 ± 7.8 kg) performed a steady-state test on a cyclergometer for 90 minutes at a moderate to high exercise intensity, eliciting a carbohydrate oxidation of 2–3 g·min-1 and a blood lactate concentration of 2 to 3 mM. Pre- and post-exercise glycogen content from rectus femoris muscle was measured using histochemical analysis through muscle biopsy and through high-frequency ultrasound scans using MuscleSound technology. Results: Correlations between muscle biopsy glycogen histochemical quantification (mmol·kg-1) and high-frequency ultrasound methodology through MuscleSound technology were r = 0.93 (P < 0.0001) pre-exercise and r = 0.94 (P < 0.0001) post-exercise. The correlation between muscle biopsy glycogen quantification and high-frequency ultrasound methodology for the change in glycogen from pre- and post-exercise was r = 0.81 (P < 0.0001). Conclusion: These results demonstrate that skeletal muscle glycogen can be measured quickly and noninvasively through high-frequency ultrasound using MuscleSound technology.

GROIN PAIN - BICYCLIST

HISTORY- A 33-year-old former competitive cyclist completed a 200K bicycle ride which involved climbing and descending three mountain passes in windy conditions. He presented to the clinic two days later complaining of pain in the left groin region. The patient said the pain was excruciating when se

Effects of Running an Ultramarathon on Cardiac, Hematologic, and Metabolic Biomarkers.

Serum biomarkers fluctuate as a result of running marathons, but their changes during ultramarathons have not been adequately studied. We collected blood samples from 20 participants before and 21 participants after the 161-km ultramarathon in Leadville, Colorado in August 2013. Using a portable analyzer, we measured cardiac troponin I (cTnl), hematologic, and metabolic biomarkers. Out of 10 runners for whom we collected both pre- and post-race samples, 8 were able to successfully complete the race. Mean cTnl increased from 0.001 to 0.047 ng/mL (p=0.005). Mean sodium decreased from 141 to 138 mmol/L (p <0.01). However, all runners had a sodium of ≥135 mmol/L post-race (reference range 138-146 mmol/L). Mean creatinine increased from 0.93 to 1.17 mg/dL (p <0.05). Only one out of 10 runners had an abnormal creatinine level of 1.8 mg/dL post-race (reference range 0.6-1.3 mg/dL). The other parameters did not reach statistical significance. Analyzing the samples from 21 runners after the race revealed that runners who finished the race in faster time had higher cTnl levels compared to those who finished the race close to the 30-hour cut-off finish time (P=0.005). Running an ultramarathon caused significant changes in cardiac and metabolic parameters. Ultramarathon running intensity and finish time may have effects on post-race cTnl level.

Percutaneous Ultrasound-Guided Hydrodissection of a Symptomatic Sural Neuroma.

Symptomatic neuromas of the sural nerve are a rare but significant cause of pain and debilitation in athletes. Presentation is usually in the form of chronic pain and dysesthesias or paresthesias of the lateral foot and ankle. Treatment traditionally ranges from conservative measures, such as removing all external compressive forces, to administration of nonsteroidal anti-inflammatory drugs, vitamin B6, tricyclic antidepressants, antiepileptics, or topical anesthetics. This article reports a case of sural nerve entrapment in a 34-year-old male triathlete with a history of recurrent training-induced right-sided gastrocnemius strains. The patient presented with numbness in the right lateral foot and ankle that had persisted for 3 months, after he was treated unsuccessfully with extensive nonoperative measures, including anti-inflammatory drugs, activity modification, and a dedicated physical therapy program of stretching and strengthening. Orthopedic assessment showed worsening pain with forced passive dorsiflexion and manual pressure applied over the distal aspect of the gastrocnemius. Plain radiographs showed normal findings, but in-office ultrasound imaging showed evidence of sural nerve entrapment with edema and neuromatous scar formation in the absence of gastrocnemius or soleus pathology. Percutaneous ultrasound-guided hydrodissection of the sural nerve at the area of symptomatic neuroma and neural edema was performed the same day. The patient had complete relief of symptoms and full return to the preinjury level of participation in competitive sports. This case report shows that hydrodissection, when performed by an experienced physician, can be an effective, minimally invasive technique for neurolysis in the setting of sural nerve entrapment, resulting in improvement in clinical symptoms.

Diffuse subcutaneous upper extremity edema in the setting of rhabdomyolysis: a case report.

Introduction While exertional rhabdomyolysis (ER) can occur with any strenuous exercise, it is more common with exercise involving repetitive eccentric contractions than with concentric contractions (5). ER is the result of the breakdown of skeletal muscle fibers due to overexertion with muscle destruction, necrosis, loss of cell membrane integrity, and displacement of intracellular contents into the extracellular space (1). ER is a syndrome entailing muscle soreness, weakness, and possibly brown urine (13). Complications of ER may include acute kidney injury (AKI), compartment syndrome, hyperkalemia, disseminated intravascular coagulation (DIC), and hypocalcemia (1). Diagnosis of rhabdomyolysis is made by clinical evidence of muscle damage and the presence of circulatory muscle cell content including creatine kinase (CK) and myoglobin (16). Elevation in serum myoglobin declines rapidly and may not be present at the time of presentation. Urine myoglobin test may take several days so it cannot be relied upon for treatment decisions. It is generally acknowledged that an increase in CK of five times the upper limit of normal, with symptoms of muscle pain or muscle weakness, and dark urine in the setting of strenuous activity are indicative of ER (3,14).

randomized controlled trial of Micro-Mobile compression ® on lactate clearance and subsequent exercise performance in elite male cyclists

Background The purpose of this paper was to assess the feasibility of Micro-Mobile Compression® (MMC) on lactate clearance following exhaustive exercise and on subsequent exercise performance. Methods Elite male cyclists were randomized to MMC (n = 8) or passive recovery (control, n = 8). MMC is incorporated into a sandal that intermittently compresses the venous plexus during non-weight bearing to augment venous return. On day 1, subjects performed a graded exercise test on a cycle ergometer followed by 60 minutes of seated recovery, with or without MMC. Blood lactate concentration ([La−]) was measured during exercise and recovery. Subjects returned home for 3 more hours of seated recovery, with or without MMC. On days 2 and 3, subjects exercised to exhaustion in a fixed-load cycle ergometer test at 85% peak power and then repeated the day 1 post-exercise recovery procedures. Lactate clearance data after the time to exhaustion tests on days 2 and 3 were averaged to adjust for interday variation. Results On the day after MMC or control recovery, mean time to exhaustion was 15% longer (mean difference, 2.1 minutes) in the MMC group (P = 0.30). The standardized mean difference of MMC for time to exhaustion was 0.55, defined as a moderate treatment effect. Following the graded exercise test, area under the 60-minute lactate curve was nonsignificantly lower with MMC (3.2 ± 0.4 millimolar [mM]) versus control (3.5 ± 0.4 mM, P = 0.10) and times from end of exercise to 4mM and 2mM were 2.1 minutes (P = 0.58) and 7.2 minutes (P = 0.12) shorter, although neither achieved statistical significance. Following time to exhaustion testing, the area under the 60-minute lactate curve was lower with MMC (3.2 ± 0.2 mM) versus control (3.5 ± 0.2 mM, P = 0.02) and times from end of exercise to 4mM and 2mM were 4.4 minutes (P = 0.02) and 7.6 minutes (P < 0.01) faster. The standardized mean difference of MMC on most lactate clearance parameters was >0.8, defined as a large treatment effect. Conclusion MMC yields large treatment effects on lactate clearance following high-intensity exercise and moderate treatment effects on subsequent exercise performance in elite male cyclists.

Sports Ultrasound: Applications Beyond the Musculoskeletal System.

Background: Traditionally, ultrasound has been used to evaluate musculoskeletal injuries in athletes; however, ultrasound applications extend well beyond musculoskeletal conditions, many of which are pertinent to athletes. Evidence Acquisition: Articles were identified in PubMed using the search terms ultrasound, echocardiogram, preparticipation physical examination, glycogen, focused assessment with sonography of trauma, optic nerve, and vocal cord dysfunction. No date restrictions were placed on the literature search. Study Design: Clinical review. Level of Evidence: Level 4. Results: Several potential applications of nonmusculoskeletal ultrasound in sports medicine are presented, including extended Focused Assessment with Sonography for Trauma (eFAST), limited echocardiographic screening during preparticipation physical examinations, assessment of muscle glycogen stores, optic nerve sheath diameter measurements in athletes with increased intracranial pressure, and assessment of vocal cord dysfunction in athletes. Conclusion: Ultrasound can potentially be used to assist athletes with monitoring their muscle glycogen stores and the diagnosis of multiple nonmusculoskeletal conditions within sports medicine.

In Reply to Dr Lankford

To the Editor: We read with enthusiasm the letter from Dr Lankford in response to our recently published letter to the editor “Ultraendurance athletes with type 1 diabetes: Leadville 100 experience.” We are pleased that our findings have started to generate discussion among clinicians and researchers. As Dr Lankford mentioned in his letter, there is a lack of specific guidelines for endurance athletes with type 1 diabetes mellitus (DM1). Anecdotally, most of our athletes with DM1 did not use insulin pumps. Although we had glucose monitoring capabilities at our medical aid stations, most of our athletes with DM1 used their own glucose monitors. Unfortunately, we are unable to answer any other specific questions raised by Dr Lankford owing to the retrospective nature of our study. We hope this reply has made it clear that until we have large-scale prospective studies, an individualized and well-thought-out plan designed and reviewed by the athletes with DM1, the athletes’ physicians, and the race medical team should be used to achieve optimal glycemic control during these long races. In addition to the standard medical alert bracelets, we recommend using medical wristbands for each athlete highlighting the information about pertinent medical conditions, medications, and allergies.