The effect of a 2-week ischaemic preconditioning intervention on anaerobic performance in male academy football players: a randomized, single-blinded, SHAM-Controlled study

Figures & data

Figure 1. Schematic of experimental study design.

Figure 2. (A) peak power output and (b) mean power output before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials. Bars = mean, error bars = ±SD.

* IPC significantly higher than SHAM at POST (p<0.05).

Table 1. Running-based anaerobic sprint test performance before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials (mean±sd).

	IPC		SHAM		p-value and partial eta squared
	PRE	POST	PRE	POST	Time	Condition	Interaction
Peak Power Output (W)	632.8 ± 199.1	708.6 ± 217.6*	640.5 ± 166.2	572.3 ± 174.2	p = 0.851, η^2 = 0.005	p = 0.102, η^2 = 0.337	p = 0.010, η^2 = 0.639
Mean Power Output (W)	504.6 ± 170.0^#	559.7 ± 168.9^#^	496.1 ± 145.9	460.0 ± 161.2	p = 0.661, η^2 = 0.029	p = 0.031, η^2 = 0.509	p = 0.047, η^2 = 0.453
Maximal Heart Rate (bpm)	183 ± 9	182 ± 10	179 ± 7	180 ± 11	p = 0.966, η^2 = 0.001	p = 0.263, η^2 = 0.175	p = 0.647, η^2 = 0.032
Blood Lactate (mmol/L)	9.50 ± 3.90	9.41 ± 2.35	8.49 ± 2.79	7.78 ± 2.81	p = 0.535, η^2 = 0.057	p = 0.118, η^2 = 0.312	p = 0.720, η^2 = 0.020
Fatigue Index (W/sec)	5.53 ± 2.49	6.95 ± 2.80^+	6.46 ± 2.25	5.08 ± 1.96	p = 0.960, η^2 = 0.001	p = 0.551, η^2 = 0.053	p = 0.013, η^2 = 0.608

*Significant main effect for interaction (p = 0.010) with IPC POST higher than SHAM POST.

^Significant main effect for interaction (p=0.047) with IPC POST higher than SHAM POST.

⁺Significant main effect for interaction (p = 0.013) with IPC POST higher than SHAM POST.

^#Significant main effect for condition (p = 0.031) with IPC higher than SHAM.

Figure 3. Superficial femoral artery flow-mediated dilation (FMD) before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials. Bars = mean, error bars = ±SD.

* IPC significantly higher than SHAM at POST (p<0.05).

Table 2. Superficial femoral artery flow-mediated dilation (FMD) before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials (mean±sd).

	IPC		SHAM		p-value and partial eta squared
	PRE	POST	PRE	POST	Time	Condition	Interaction
Relative FMD (%)	4.68 ± 2.04	6.40 ± 2.14*	6.67 ± 3.18	4.96 ± 2.65	p = 0.992, η^2 = 0.001	p = 0.815, η^2 = 0.008	p = 0.017, η^2 = 0.577
Relative FMD (%) allometric modelling	4.84 ± 2.21	6.29 ± 2.21^#	6.40 ± 2.23	3.77 ± 2.23	p = 0.485, η^2 = 0.018	p = 0.527, η^2 = 0.015	p = 0.020, η^2 = 0.185
Absolute FMD (mm)	6.69 ± 0.69	6.69 ± 0.74	6.55 ± 0.91	6.71 ± 0.38	p = 0.660, η^2 = 0.029	p = 0.606, η^2 = 0.040	p = 0.640, η^2 = 0.033
Baseline Diameter (mm)	6.39 ± 0.72	6.29 ± 0.69	6.15 ± 0.89	6.48 ± 0.40	p = 0.462, η^2 = 0.080	p = 0.825, η^2 = 0.007	p = 0.141, η^2 = 0.282
Shear Rate AUC (s^−1 x 10^3)	4.4 ± 6.4	8.5 ± 6.0	10.6 ± 2.9	10.1 ± 7.1	p = 0.351, η^2 = 0.125	p = 0.346, η^2 = 0.127	p = 0.347, η^2 = 0.127

*Significant main effect for interaction (p = 0.017) with IPC POST higher than SHAM POST.

^#Significant main effect for interaction (p = 0.020) with IPC POST higher than SHAM POST.

Shear Rate AUC- Shear Rate Area Under the Curve.

Table 3. Resting physiological measurements taken before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials (mean±sd).

	IPC		SHAM		p-value and partial eta squared
	PRE	POST	PRE	POST	Time	Condition	Interaction
Heart Rate (bpm)	61 ± 11	64 ± 13	57 ± 6	65 ± 14	p = 0.072, η^2 = 0.339	p = 0.528, η^2 = 0.053	p = 0.468, η^2 = 0.608
Systolic Blood Pressure (mmHg)	120.6 ± 9.9	124.5 ± 9.9	117.8 ± 7.5	122.0 ± 9.7	p = 0.347, η^2 = 0.160	p = 0.506, η^2 = 0.087	p = 0.921, η^2 = 0.0001
Diastolic Blood Pressure (mmHg)	71.4 ± 2.6	68.1 ± 5.8	66.5 ± 3.3	67.9 ± 18.9	p = 0.814, η^2 = 0.023	p = 0.460, η^2 = 0.155	p = 0.522, η^2 = 0.425
Blood Lactate (mmol/L)	1.32 ± 0.27	1.58 ± 0.31*	1.16 ± 0.13	1.44 ± 0.40*	p = 0.035, η^2 = 0.533	p = 0.392, η^2 = 0.141	p = 0.950, η^2 = 0.002

*Significant main effect for time (p = 0.035) with POST higher than PRE.

Table 4. Measures of sleep and training load before (PRE) and after (POST) the completion of the ischaemic preconditioning (IPC) and SHAM-controlled (SHAM) trials (mean±sd).

	IPC			SHAM		p-value and partial eta squared
	PRE	POST		PRE	POST	Time	Condition	Interaction
Sleep
SF Index	32.5 ± 17.9	33.6 ± 13.0		45.1 ± 15.3	41.1 ± 13.0	p = 0.757, η^2 = 0.015	p = 0.158, η^2 = 0.263	p = 0.636, η^2 = 0.034
Sleep Efficiency (%)	76.8 ± 10.4	81.5 ± 10.6		72.8 ± 11.0	71.2 ± 8.6	p = 0.601, η^2 = 0.041	p = 0.125, η^2 = 0.303	p = 0.264, η^2 = 0.174
Total Minutes in Bed (mins)	609 ± 106*	644 ± 61*		447 ± 64	482 ± 81	p = 0.409, η^2 = 0.001	p = 0.001, η^2 = 0.847	p = 0.982, η^2 = 0.099
Sleep Duration (mins)	447 ± 82	456 ± 52		347 ± 85	395 ± 100	p = 0.197, η^2 = 0.136	p = 0.064, η^2 = 0.407	p = 0.329, η^2 = 0.225
Training Load
Session-RPE (A.U.)	5.38 ± 3.38	3.63 ± 4.00		4.50 ± 3.78	4.00 ± 3.38	p = 0.161, η^2 = 0.260	p = 0.351, η^2 = 0.125	p = 0.460, η^2 = 0.080

*Significant main effect for condition (p = 0.001) with IPC higher than SHAM.

SF Index- Sleep Fragmentation Index.

Session-RPE- Session-Rating of Perceived Exertion, A.U.- arbitrary units.

Data availability statement

The data that support the findings of this study are available from the corresponding author, ESS, upon reasonable request.