The sport of triathlon is popular, especially among recreational athletes. USA Triathlon, the national governing body of the sport in the United States, was founded in 1982 and has grown to over 40,000 members with more than 4000 sanctioned races each year (1). Athletes compete in shorter races ranging from around 16 miles to the 140.6-mile Ironman, which is traditionally the longest triathlon distance. Training in three disciplines simultaneously, triathletes usually have a higher total training volume than single-sport athletes. However, this diversity also allows the athletes to modify their training while maintaining fitness when injuries occur (2). Previous studies looking at the rate of injury among triathletes indicate that musculoskeletal injuries are common. Overuse injuries were often reported, but traumatic injuries, such as contusion, abrasions, and fractures, also occurred. Injuries were reported by 36.8% to 91% of the athletes included in previous studies (3–8). This wide range could be because of the differences in the length of time athletes were followed or the distance of the race for which they were training. For example, one of the lowest rates of injury reported by Korkia et al. (5) was determined from only a 6-wk study period. Additionally, these studies also included athletes of different levels, from recreational to professional. In the current study, we used survey data to characterize training habits, injuries, and lifestyle factors such as nutrition and supplement use in a group of recreational triathletes. Previous studies have looked at the relationship between training and injury. Here, we looked at the athletes’ habits including medical and lifestyle variables in addition to training and injury information to provide a comprehensive evaluation of variables that may contribute to injury risk and recovery from injury.
Participants included triathletes older than 18 years. They were recruited by advertising among triathlon clubs and training groups in the Miami, Florida area and from patients who presented to the University of Miami Sports Medicine clinic for evaluation and follow-up. Triathletes were defined as any athlete who had completed a triathlon in the year prior to completing the survey or was planning to do a triathlon in the coming year. Volunteers provided their e-mail address, and a link to the survey was then sent to their e-mail. After consenting to participation, they completed the survey online. The study design was approved by the institutional review board of the University of Miami.
The invitation to complete the survey was sent to 131 athletes. Fifty completed the survey, giving a response rate of 38%. Sixteen responses did not meet the definition of triathlete, so a total of 34 triathletes were included in the study. Nine (26%) were recruited from the clinic and 25 (74%) were recruited from community clubs. The average age of the participants was 47.6 years (range, 24 to 78 years). One third of the participants were female, and two-thirds were male. Average body mass index (BMI) was 25.8 kg·m2. Among females, the average BMI was 23.6 kg·m2 (range, 18.3 to 31.5 kg·m2). The male athletes had a slightly higher average BMI of 27.1 kg·m2 (range, 22.3 to 39.3 kg·m2). Seventy-nine percent reported at least one current area of pain or injury. Twenty-six percent reported more than one current area of pain or injury, with the most being four. When asked about previous injuries, 79% reported an injury or pain which was severe enough to cause limitations or modifications of their training. Forty-seven percent reported more than one injury in the past. Athletes who had completed a half or full Ironman distance race reported an average of two past injuries while those who had completed only sprint or Olympic distance races reported an average of 1.1 injuries in the past. Similarly, they reported an average of 3.06 total injuries (current or in the past) compared with an average of 2.53 reported by athletes who had completed an Olympic or sprint distance race.
The lower extremity, including hip, knee, leg, foot, and ankle, represented 72% of all pain and injuries reported. The leg was the most common location reported, accounting for 17% of pain and injuries. The hip, knee, and foot each accounted for 16%. Other locations reported include the back (6%), neck (7%), and shoulder (15%). No athlete reported arm pain or injury. The most common interventions used for treatment included physical therapy, ice, and rest (Fig. 1).
In regard to training, athletes spent the most training time per week biking at an average of 4.9 h, followed by running at 3.5 h, and then swimming at 2.1 h. The time an athlete spent swimming ranged from 0 to 4 h·wk−1. The range of time spent biking and running were greater at 0 to 20 h·wk−1 and 0 to 10 h·wk−1, respectively. Weight training was reported by 56% of athletes. Only 15% participated in some type of yoga or Pilates. The average total time spent in training was 11.8 h·wk−1, with a range of 4 to 35 h·wk−1. Those planning to complete a half or full Ironman length race trained an average of 12.6 h·wk−1, while those planning for only sprint or Olympic distance races reported an average of 10.8 h of training per week. Athletes who reported training less than 12 h·wk−1 had an average of 2.3 injuries, while those who train 12 or more hours per week reported a slightly higher average of 3.3 injuries. Most athletes, 65%, trained with the help of a coach. Only 38% reported working with a nutritionist, and 6% reported working with a sports psychologist (Fig. 2).
Most athletes reported no dietary restrictions. However, 15% followed a gluten-free diet, 6% reported a vegan diet, and 9% a vegetarian diet. Additionally, 15% reported a lactose-free diet. Although these groups are small, all of the athletes following a gluten-free, vegan, or vegetarian diet reported an injury. Injuries were reported by 80% of athletes following a lactose-free diet.
Sixty-five percent of athletes used some type of vitamin or supplement, with multivitamins being the most common. Multivitamins were used by 47% of the athletes and accounted for 30% of the supplements reported. Thirty percent of athletes used an individual vitamin supplement, and 26% used a protein supplement. Other commonly used supplements included calcium, iron, and fish oil used by 15%, 9%, and 15%, respectively. Interestingly, only one female athlete (9% of all female athletes) reported no supplement use, while 11 male athletes (50% of all male athletes) did not use any type of supplement (Fig. 3).
Athletes also were asked about their medical history. Commonly reported conditions included hypertension, anxiety, allergies, asthma, and thyroid disease. Among participants, 16 responded to a question regarding their sleep habits. Sixty-three percent report sleeping 6 h or less per night. No one reported more than 9 h of sleep per night.
Our study confirmed previous reports that triathletes represent a diverse group of individuals, with a wide range of ages, body compositions, medical histories, and training regimens. Additionally, these athletes report diverse lifestyle habits. Regarding their nutritional practices, many reported no dietary restrictions, but many of the athletes reported limiting or eliminating certain foods or ingredients. Previously, a study looking at diet in triathletes examined whether athletes were meeting recommendations for macronutrient intake, including protein and carbohydrates. Masson and Lamarche (9) found that less than half of the athletes met the recommendations for carbohydrate intake. This deficit may be of particular concern for the 15% of athletes in our study who reported a gluten-free diet if they replace gluten-containing carbohydrates with proteins or fats. Additionally, only around two thirds met the upper limit of protein intake in the study, which could be a concern for the 15% of our participants reporting a vegetarian or vegan diet (9). A lactose-free diet was reported by 15% of our subjects, which may put them at risk for vitamin D and calcium deficiency. Both micronutrients also are known to be important in bone health, and vitamin D also has been shown to play a role in muscle recovery. Barker et al. (10) found that vitamin D supplementation enhanced recovery of leg muscle force after damaging exercise. Similarly, Owens et al. (11) found that vitamin D supplementation improved the recovery of peak torque of the knee extensors following damaging eccentric exercise. Only one other study has looked at supplement use in triathletes. Dolan et al. (12) evaluated supplement use specifically as a strategy for race preparation, with just over half of participants reporting supplement use in their race preparation. Approximately 40% reported using multivitamin or mineral supplements, and approximately 30% used protein supplements. There was not a significant difference between male and female athletes, with 54.6% of male athletes and 52.6% of female athletes using supplements. Herein, we looked more closely at the specific supplements used regularly by triathletes. Almost two thirds of our subjects reported some type of supplement use, with 60% noting use of more than one type of supplement, including multivitamins, individual vitamins, calcium, iron, fish oil, protein, and workout boosters.
The current study found a high rate of injuries among recreational triathletes. Seventy-nine percent of our athletes reported a current pain or injury, and 79% had a history of pain or injury during training that caused an alteration in their regimen. Our injury rate is among the higher rates previously reported (3–8). This may be in part because of recruiting 26% of our participants from a sports medicine clinic since they were most likely presenting with an injury. Our study found that the lower extremity was the most common location of reported pain and injury. This finding is consistent with previous studies as well. Andersen and colleagues (3) reported the most common location for acute and overuse pain among a group of Ironman athletes was the knee, followed by the lower leg. Similarly, knee injuries were found to be the most common in a study of British national team members (13). Another study of triathletes training for races of all distances reported the lower extremity as the most common site of injury, with ankle and foot more common than knee injuries (5). Shoulder pain is the most common injury among competitive swimmers (14). However, our participants reported a low rate of shoulder pain and injury. This may be related to the volume of swim training in which the athletes participate. Training volumes were shown to be related to the incidence of shoulder pain in a recent systematic review of swimmers. Feijen et al. (15) found that the training volume in adult competitive swimmers ranged from 8.75 to 26.8 h·wk−1, which is much more than the 2.5 h·wk−1 averaged by our study participants.
Previously, studies also have looked for anthropometric factors associated with increased risk of injury among triathletes. Multiple reports found no association between gender, age, height, weight, or BMI and injury incidence (5,12,13). Associations between training load and injury also have been investigated with mixed results. Korkia and colleagues (5) found no association between weekly total training distance, training time, or the number of weekly workouts and injury incidence over 8 wk. Similarly, training distance per week, average training pace, and average training time per week were shown not to be associated with injury risk (6,16). However, positive associations also have been found between more specific training variables. Total run training time, speed training, and distance covered running hills have been positively associated with injuries (13). Additionally, a positive relationship between weekly training hours and muscle and tendon injury was shown among a group of Ironman athletes (4). Our study found that athletes who had completed a half or full Ironman race in the past reported higher rates of injuries. We also found that athletes training for 12 or more hours per week had a higher number of injuries on average.
We have highlighted the diversity among recreational triathletes, both in physical characteristics, as well as training, suggesting that injury risk for these athletes is most likely composed of complex interactions between many variables. Furthermore, it is likely different for each athlete, so an individual approach for training should be considered. This is supported by studies that found previous injuries were a risk factor for future injury (16,17). Individual specific training is consistent with a comprehensive approach to injury risk proposed by Meeuwisse and colleagues (18). They propose that the relationship between risk factors and injury is not a linear relationship, and that multiple risk factors interact and can change over time. Future studies should, therefore, assess potential risk factors and how they change over time.
There are several limitations to our study. First, the sample size was small. Athletes also were all recruited from the same geographical area. Triathletes training in South Florida most likely have differing training patterns than those in other parts of the United States or the world where the weather is more seasonal, potentially limiting training during certain parts of the year. There also is a selection bias because many of our study participants were recruited from clinic, and athletes who have or had an injury may be more likely to volunteer to participate in the study. Additionally, there was no specific definition of injury given, and athletes were asked to recall previous injuries retrospectively.
The sport of triathlon is popular among recreational athletes. The goal of this study was to characterize physical and lifestyle characteristics of these athletes along with training habits and injury patterns. Results show a diverse group of athletes and, as in previous studies, we found a high rate of injuries. A better understanding of the characteristics of triathletes can guide further research on injury risk factors and inform recommendations for injury prevention.
The authors declare no conflict of interest and do not have any financial disclosures.
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