Increased air temperature decreases high-speed, but not total distance, in international field hockey

Figures & data

Table 1. Mean ± SD of volume and intensity metrics for all matches and for each condition (COOL, WARM, HOT, and VHOT).

Variable	Whole data set (n = 71)	Relationship with Temperature	Relationship with absolute humidity	Relationship with relative humidity	Relationship with WBGT	Regression Model (Temperature)	Regression Model (absolute humidity)	Regression Model (WBGT)	COOL (n = 14)	WARM (n = 10)	HOT (n = 31)	VHOT (n = 16)
Environmental parameters
Temperature (°C)	25.0 ± 6.5	-	-	-	-	-	-	-	13.5 ± 3.1 ^## ^^ ^vv	23.6 ± 1.0 *** ^^ ^vv	27.3 ± 1.0 ** ^## vv	31.5 ± 2.4 ** ^## ^^
Absolute humidity (g.m^3)	15.9 ± 5.9	r = 0.637 ^††	-	-	-	-	-	-	8.7 ± 2.3 ^## ^^ ^vv	13.7 ± 3.8 *** ^^ ^vv	18.2 ± 4.2 ** ^##	19.4 ± 6.1 ** ^##
Relative humidity (%)	67 ± 17	r = −0.209	r = 0.581 ^††	-	-	-	-	-	72 ± 14	64 ± 17	70 ± 16	60 ± 20
WBGT (°C)	22.0 ± 5.4	r = 0.892 ^††	r = 0.848 ^††	r = −0.193	-	-	-	-	11.6 ± 3.0 ^## ^^ ^vv	20.4 ± 2.0 ** ^^ ^vv	24.4 ± 2.0 ** ^## vv	26.9 ± 2.4 ** ^## ^^
Volume metrics
Playing duration (mins)	38.8 ± 1.9	r = 0.260 ^†	r = 0.163	r = −0.063	r = 0.248 ^†	b0 = 36.9 b1 = 0.075 SEE = 1.8 min ^†	b0 = 38.0 b1 = 0.052 SEE = 1.9 min ^†	b0 = 37.1 b1 = 0.079 SEE = 1.8 min ^†	38.0 ± 1.2	38.2 ± 1.1	39.3 ± 2.2	39.2 ± 1.8
Total distance (m)	4865 ± 205	r = −0.192	r = −0.153	r = −0.003	r = −0.203 ^†	b0 = 5016.5 b1 = −6.063 SEE = 202 m	b0 = 4950.6 b1 = −5.373 SEE = 204 m ^†	b0 = 5018.4 b1 = −7.024 SEE = 202 m ^†	4962 ± 146	4808 ± 171	4837 ± 212	4869 ± 241
High-speed Running (m)	1191 ± 166	r = −0.425 ^††	r = −0.444 ^††	r = −0.106	r = −0.472 ^††	b0 = 1462.1 b1 = −10.831 SEE = 151 m ^††	b0 = 1391.9 b1 = −12.570 SEE = 149 m ^††	b0 = 1480.1 b1 = −13.2 SEE = 147 m ^††	1318 ± 103	1249 ± 113	1139 ± 173 **	1145 ± 163 *
Low-speed Running (m)	3664 ± 164	r = 0.184	r = 0.249 ^†	r = 0.100	r = 0.216 ^†	b0 = 3548.4 b1 = 4.627 SEE = 162 m	b0 = 3552.7 b1 = 6.977 SEE = 160 m ^†	b0 = 3533.3 b1 = 5.987 SEE = 161 m ^†	3636 ± 114	3550 ± 105	3688 ± 191	3715 ± 146
Sprinting (m)	401 ± 74	r = −0.299 ^†	r = −0.259 ^†	r = 0.005	r = −0.305 ^††	b0 = 485.1 b1 = −3.381 SEE = 71 m ^†	b0 = 452.1 b1 = −3.226 SEE = 72 m ^††	b0 = 483.5 b1 = −3.793 SEE = 71 m ^††	436 ± 51	431 ± 55	383 ± 83	385 ± 69
Sprinting Efforts (n)	21 ± 3	r = −0.335 ^††	r = −0.309 ^††	r = −0.019	r = −0.352 ^††	b0 = 25.2 b1 = −0.165 SEE = 3 ^††	b0 = 23.8 b1 = −0.169 SEE = 3 ^††	b0 = 25.2 b1 = −0.190 SEE = 3 ^††	23 ± 2	22 ± 2	20 ± 4	20 ± 3
Playerload (a.u.)	470 ± 23	r = −0.298 ^†	r = −0.300 ^†	r = −0.063	r = −0.333 ^††	b0 = 496.4 b1 = −1.075 SEE = 23 a.u. ^†	b0 = 488.7 b1 = −1.201 SEE = 23 ^††	b0 = 498.4 b1 = −1.318 SEE = 22 ^††	483 ± 19	473 ± 19	464 ± 24	466 ± 25
Acceleration Efforts (n)	50 ± 3	r = −0.199	r = −0.122	r = 0.054	r = −0.185	b0 = 52.2 b1 = – 0.105 SEE = 3	b0 = 50.8 b1 = −0.072 SEE = 3	b0 = 51.9 b1 = −0.107 SEE = 3	51 ± 3	49 ± 3	50 ± 4	48 ± 3
Deceleration Efforts (n)	60 ± 4	r = −0.357 ^††	r = −0.325 ^†	r = −0.016	r = −0.374 ^††	b0 = 65.3 b1 = −0.232 SEE = 4 ^††	b0 = 63.3 b1 = −0.235 SEE = 4 ^††	b0 = 65.4 b1 = −0.267 SEE = 4 ^††	62 ± 4	59 ± 4	59 ± 4 *	58 ± 4 *
VHI movements (n)	17 ± 2	r = −0.063	r = −0.036	r = −0.050	r = 0.051	b0 = 18.2 b1 = −0.025 SEE = 2	b0 = 17.5 b1 = −0.012 SEE = 2	b0 = 17.7 b1 = −0.016 SEE = 2	17 ± 2	18 ± 2	18 ± 2	16 ± 2
Intensity metrics
Average speed (m.min^−1)	127.4 ± 5.8	r = −0.479 ^††	r = −0.315 ^††	r = 0.067	r = −0.459 ^††	b0 = 138.1 b1 = −0.429 SEE = 5.1 m.min^−1 ††	b0 = 132.4 b1 = −0.313 SEE = 5.6 m.min^−1 ††	b0 = 137.2 b1 = −0.451 SEE = 5.2 m.min^−1 ††	133.1 ± 3.1	127.7 ± 4.6	125.3 ± 5.1 **	126.2 ± 6.7 **
High-speed running (m.min^−1)	32 ± 5	r = −0.506 ^††	r = −0.311 ^††	r = −0.068	r = −0.449 ^††	b0 = 41.3 b1 = −0.367 SEE = 4 m.min^−1 ††	b0 = 36.2 b1 = −0.249 SEE = 5 m.min^−1 ††	b0 = 40.0 b1 = −0.356 SEE = 4 m.min^−1 ††	36 ± 3	34 ± 3	30 ± 5 **	31 ± 4 **
Low-speed running (m.min^−1)	95 ± 4	r = −0.110	r = −0.104	r = 0.180	r = −0.155	b0 = 96.6 b1 = −0.066 SEE = 4 m.min^−1	b0 = 96.0 b1 = −0.068 SEE = 4 m.min^−1	b0 = 97.1 b1 = −0.100 SEE = 4 m.min^−1	96 ± 2	93 ± 2	95 ± 4	95 ± 5
Sprinting (m.min^−1)	10.9 ± 2.1	r = −0.367 ^††	r = −0.194	r = 0.026	r = −0.290 ^††	b0 = 13.8 b1 = −0.117 SEE = 1.9 m.min^−1 ††	b0 = 12.0 b1 = −0.068 SEE = 2.0 m.min^−1 ††	b0 = 13.1 b1 = −0.100 SEE = 2.0 m.min^−1 ††	12.1 ± 1.3	11.8 ± 1.6	10.3 ± 2.3 *	10.4 ± 1.8
Sprinting efforts (n.min^−1)	0.6 ± 0.1	r = −0.404 ^††	r = −0.235 ^†	r = 0.011	r = −0.359 ^††	b0 = 0.7 b1 = −0.006 SEE = 0.1 n.min^−1 ††	b0 = 0.6 b1 = −0.004 SEE = 0.1 n.min^−1 ††	b0 = 0.7 b1 = −0.005 SEE = 0.1 n.min^−1 ††	0.6 ± 0.0	0.6 ± 0.1	0.5 ± 0.1 *	0.5 ± 0.1 *
Playerload (a.u.min^−1)	12.3 ± 0.7	r = −0.467 ^††	r = −0.297 ^†	r = 0.004	r = −0.417 ^††	b0 = 13.7 b1 = −0.052 SEE = 0.7 a.u. min^−1 ††	b0 = 12.9 b1 = −0.037 SEE = 0.7 a.u. min^−1 ††	b0 = 13.5 b1 = −0.052 SEE = 0.7 a.u. min^−1 ††	13.0 ± 0.6	12.6 ± 0.6	12.1 ± 0.7 **	12.2 ± 0.7 *
Acceleration efforts (n.min^−1)	1.3 ± 0.1	r = −0.293 ^†	r = −0.256 ^†	r = 0.087	r = −0.293 ^††	b0 = 1.4 b1 = −0.005 SEE = 0.1 ^†	b0 = 1.4 b1 = −0.005 SEE = 0.1 ^††	b0 = 1.4 b1 = −0.006 SEE = 0.1 ^††	1.4 ± 0.1	1.3 ± 0.1	1.3 ± 0.1	1.3 ± 0.1
Deceleration efforts (n.min^−1)	1.6 ± 0.1	r = −0.408 ^††	r = −0.347 ^††	r = −0.007	r = −0.406 ^††	b0 = 1.8 b1 = −0.009 SEE = 0.1 ^††	b0 = 1.7 b1 = −0.008 SEE = 0.1 ^††	b0 = 1.4 b1 = −0.006 SEE = 0.1 ^††	1.7 ± 0.1	1.6 ± 0.1	1.5 ± 0.1 *	1.5 ± 0.1 *
VHI movements (n.min^−1)	0.5 ± 0.1	r = −0.168	r = −0.127	r = 0.021	r = −0.148	b0 = 0.5 b1 = −0.002 SEE = 0.1	b0 = 0.5 b1 = −0.002 SEE = 0.1	b0 = 0.5 b1 = −0.002 SEE = 0.1	0.5 ± 0.1	0.5 ± 0.1	0.5 ± 0.0	0.4 ± 0.1

† denotes significant correlation with temperature (p < 0.05), †† denotes significant correlation with temperature (p < 0.01)

* denotes significant difference from COOL (p < 0.05), ** denotes significant difference from COOL (p < 0.01)

# denotes significant difference from WARM (p < 0.05), ## denotes significant difference from WARM (p < 0.01)

^ denotes significant difference from HOT (p < 0.05), ^^ denotes significant difference from HOT (p < 0.01)

^adenotes significant difference from VHOT (p < 0.05), ^vv denotes significant difference from VHOT (p < 0.01)

WBGT = Wet-bulb globe temperature

SEE = Standard error of the estimate

Figure 1. Panel of scatter plots demonstrating the relationship between temperature and volume (panels a-d) and intensity (panels e-h) metrics.

* denotes p < 0.05. High-speed running = >14.5 km.h⁻¹ and sprinting = >19 km.h⁻¹.

Figure 2. Mean ± SD panel of selected volume (panels B&C) and intensity (panels D-I) metrics depicting responses across conditions (COOL, WARM, HOT, VHOT).

Filled circles depict individual data points. * denotes significant difference from COOL (p < 0.05), # denotes significant difference from WARM (p < 0.05), ^ denotes significant difference from HOT (p < 0.05). High-speedrunning = >14.5 km.h⁻¹, low-speedrunning = <14.5 km.h⁻¹ and sprinting = >19 km.h⁻¹. Acceleration and deceleration efforts = >2 or <-2 m. s⁻², respectively.

Figure 3. Summary figure outlining the change (%) in volume (a) and intensity (b) metrics in COOL, WARM, HOT and VHOT from the group mean.

* denotes main effect of temperature for each variable (p < 0.05). High-speedrunning = >14.5 km.h⁻¹, low-speedrunning = <14.5 km.h⁻¹ and sprinting = >19 km.h⁻¹. Acceleration and deceleration efforts = >2 or <-2 m. s⁻², respectively. VHI movements = sum of all movements in the horizontal plane (i.e. accelerations, decelerations, and left/right changes of direction), when >3.5 or <-3.5 m s⁻².

Figure 4. Mean ± SD panel of positional responses across conditions (COOL, WARM, HOT, VHOT).

* denotes within position difference from COOL (p < 0.05), + denotes within position difference from WARM (p < 0.05). High-speedrunning = >14.5 km.h⁻¹, low-speedrunning = <14.5 km.h⁻¹ and sprinting = >19 km.h⁻¹.

Figure 5. Panel of A – average speed (m.min⁻¹), B – high speed running (m.min⁻¹), C – low speed running (m.min⁻¹), and D – sprinting distance (m.min⁻¹) responses across playing quarters and conditions (circle = COOL, square = WARM, triangle = HOT, nabla = VHOT). Error bars removed for clarity.

* denotes a difference between COOL and WARM, ^ denotes a difference between COOL and HOT, + denotes a difference between COOL and VHOT, # denotes a difference between WARM and HOT, v denotes a difference between WARM and VHOT, all p < 0.05. High-speedrunning = >14.5 km.h⁻¹, low-speedrunning = <14.5 km.h⁻¹ and sprinting = >19 km.h⁻¹.

Table

AIR	Air temperature
ANOVA	Analysis of variance
FIFA	Federation Internationale de Football Association
GPS	Global positioning system
HDOP	Horizontal dilution of precision
IMA	Inertial movement analysis
Q1, Q2, Q3, Q4	Respective playing quarters
R.H.	Relative humidity
SWC	Smallest worthwhile change
VHI	Very high intensity
WBGT	Wet-bulb globe temperature
WR	World Ranking