Prevalence and burden of health problems in competitive adolescent distance runners: A 6-month prospective cohort study

Figures & data

Figure 1. Study flow chart illustrating participant recruitment, enrolment, and dropout. N.B. Due to the nature of data collection, it is not possible to confirm whether all 443 athletes received study information. Only the athletics clubs confirmed receipt of this information

Table 1. Participant characteristics (data presented as mean and SD, unless otherwise stated)

Characteristic	Overall (n = 136)	Female athletes (n = 73)	Male athletes (n = 63)	p-Value	Effect Size
Chronological age, years	15.9 (1.3)	15.8 (1.3)	16.1 (1.2)	0.15	0.25
Training age, years	5.2 (2.1)	5.6 (2.1)	4.8 (1.9)	0.04	0.36
Age-group (n, %):				X^2 = 0.67
13–14 years	26 (19%)	19 (26%)	7 (11%)
15–16 years	72 (53%)	37 (51%)	35 (56%)
17–18 years	38 (28%)	17 (23%)	21 (33%)
Stature, cm	171.0 (8.7)	166.1 (6.8)	176.6 (7.1)	<0.01	1.52
Body mass, kg	54.3 (9.1)	50.2 (6.9)	59.0 (9.1)	<0.01	1.10
Maturity timing (n, %)				X^2 = 0.08
Pre-PHV	0 (0%)	0 (0%)	0 (0%)
At-PHV	7 (5%)	6 (8%)	1 (2%)
Post-PHV	129 (95%)	67 (92%)	62 (98%)
Maturity tempo (n, %)				X^2 = 0.26
Early	1 (1%)	1 (1%)	0 (0%)
Average	128 (94%)	70 (96%)	58 (92%)
Late	7 (5%)	2 (3%)	5 (8%)
Injury in previous 12 months				X^2 = 0.24
Yes	100 (74%)	57 (78%)	43 (68%)
No	36 (27%)	16 (22%)	20 (32%)
Current performance level (n, %):				X^2 = 0.98
Club	10 (7%)	6 (8%)	4 (6%)
County	43 (32%)	22 (30%)	21 (33%)
Regional	16 (12%)	9 (12%)	7 (11%)
National	60 (44%)	32 (44%)	28 (44%)
International	7 (5%)	4 (6%)	3 (5%)

Abbreviations: n, number; cm, centimetres; kg, kilograms; PHV, peak height velocity.

NB: Due to rounding, not all numbers add up to stated N.

Table 2. Incidence, total time loss, and cumulative severity score of all health problems, all injuries, and all illnesses (split by sex)

	Incidence				Total time loss (d)	Cumulative severity score (AU)
	Cases/athlete/year	95% CI	Cases/1,000 hours of exposure	95% CI
All health problems (n = 363)	6.8	6.13–7.53	42.6	38.4–47.1	1,433	30,218
Female athletes (n = 227)	4.3	3.7–4.8	50.5	44.1–57.5	813	17,623
Male athletes (n = 136)	2.5	2.1–3.0	33.8	28.3–40.0	620	12,595
All Injuries (n = 213)	4.0	3.5–4.6	25.0	21.8–28.6	1,058	21,121
Female athletes (n = 118)	4.0	3.3–4.8	26.2	21.7–31.4	533	10,785
Male athletes (n = 95)	4.0	3.2–4.9	23.6	19.1–28.9	525	10,336
All Illnesses (n = 150)	2.8	2.4–3.3	17.6	14.9–20.7	375	9,097
Female athletes (n = 109)	3.7	3.0–4.4	24.2	19.9–29.2	280	6,838
Male athletes (n = 41)	1.7	1.3–2.3	10.2	7.3–13.8	95	2,259

Abbreviations: d, days; AU, arbitrary unit; %, percentage; CI, confidence interval; n, number.

Table 3. Severity of time loss of all health problems, all injuries (body region and area), and all illnesses (organ system)

Classification	Cases (number)
Body region	Female athletes						Male athletes
Body area/organ system	0 days	1–7 days	8–28 days	>28 days	Total Time Loss (days)		0 days	1–7 days	8–28 days	>28 days	Total Time Loss (days)
All health problems	98	157	11	7	810		50	73	13	6	623
All injuries	49	52	5	6	530		36	50	9	6	528
Lower limb	41	45	5	5	490		31	41	8	6	488
Foot/toes	2	9	2	1	132		5	4	3	1	84
Ankle	5	2	0	0	6		4	5	2	1	76
Lower leg	11	12	1	3	224		10	18	1	2	172
Knee	12	12	1	1	92		5	7	0	2	116
Thigh	6	8	0	0	20		4	5	1	0	27
Hip/groin	5	2	1	0	16		3	2	1	0	13
Trunk	6	7	0	1	40		4	6	0	0	18
Abdomen	0	1	0	0	2		0	0	0	0	0
Lumbosacral	4	4	0	1	36		2	6	0	0	18
Thoracic spine	2	0	0	0	0		0	0	0	0	0
Chest	0	2	0	0	2		2	0	0	0	0
Upper limb	2	0	0	0	0		1	3	1	0	22
Wrist	0	0	0	0	0		0	1	0	0	4
Elbow	1	0	0	0	0		0	0	0	0	0
Shoulder	1	0	0	0	0		1	2	1	0	18
All illnesses	49	53	6	1	280		14	23	4	0	95
Upper respiratory	33	28	6	0	142		9	18	4	0	80
Lower respiratory	8	5	0	0	9		2	1	0	0	2
Gastrointestinal	2	4	0	0	7		0	1	0	0	2
Neurological	1	1	0	0	1		0	0	0	0	0
Psychological	0	2	0	0	9		1	0	0	0	0
Dermatological	0	0	0	0	0		0	1	0	0	7
Non-specific illness	4	9	0	1	101		0	1	0	0	1
Energy, load management and, nutrition	1	4	0	0	11		2	1	0	0	3

Table 4. Weekly prevalence of all health problems, substantial health problems, and time loss health problems (in percentages)

	All		Female athletes		Male athletes
	Mean	95% CI	Mean	95% CI	Mean	95% CI
All health problems	24	21–26	27	24–30	20	16–23
All injuries	16	14–18	16	15–16	16	13–18
All illnesses	8	7–10	12	9–14	4	3–6
Substantial health problems	11	9–12	10	9–12	11	9–13
All injuries	7	6–9	6	5–7	9	7–11
All illnesses	4	3–4	4	3–6	2	1–3
Time loss health problems	4	3–4	3	3–4	4	3–5
All injuries	3	2–4	3	2–4	3	2–5
All illnesses	0	0–1	1	0–1	0	0–1

Abbreviations: %, percentage; CI, confidence interval.

Figure 2. Risk matrices illustrating the relationship between severity (consequence) and incidence (likelihood) of all injuries (areas) and illnesses (systems) with three or more reported cases in a population of competitive adolescent distance runners, stratified by sex. The five most commonly affected health problems are labelled. Shading illustrates the relative importance of each health problem; the darker the colour, the greater the overall burden, and the greater the priority should be given to prevention. A supplementary file can be downloaded for access to original data, excluding means and 95% confidence intervals for health problems with less than three cases

Data availability statement

Data are available from the corresponding author upon reasonable request.