Effects of intermittent and continuous resistance training on proteinuria and hematuria in trained young women.

Sir,

Following the study of effects of endurance training on proteinuria and hematuria in untrained young females [1], we conducted an investigation surrounding the effects of resistive training (RT) on proteinuria and hematuria in 36 trained (regular practice during prior 2 years) healthy women. They aged 20–25 years (22.19 ± 1.81) with body mass index of 21.8 ± 1.51 kg/m2 and VO2max of 38.4 ± 1.54 mL/kg/min. The participants were randomly assigned into Group A (intermittent RT), Group B (continuous RT) and control Group C (each, n = 12). Two days before the RT program, the participants of Groups A and B met in a training session with the intensity of 20% of one-repetition maximum (1RM), while urine samples were obtained at pre-training1 and post-training1 (0 and 1 h) stages. A1RM is the maximum weight that can be lifted one time with proper technique, which was calculated for each movement in each trainee. The participants performed the training protocol (3 days/week) during 8 weeks with an increasing intensity rate of 5% of 1RM per week from 20 to 55%. Each session consisted of two circuits including seven 2.5-min movements consisting attempts against compression on different organs (breast, arm and foot) and lateral traction. There were 2- and 1-min resting intervals between two circuits and two movements, respectively. Indeed, the total time for each session was 65 min which included: a 10-min light warming up, RT protocol for 47 min and a cool-down exercise for 5–10 min. Group B performed each movement with a constant speed (V = one attempt per 2.5 s), continuously. Group A was asked to do each movement with different speed (2V for 10 and ½V for 20 s), intermittently. The speed of movements was controlled by a metronome. Two days after termination of training workouts, following an effort of 20% of 1RM, similar urine samples were collected as pre-training2 and post-training2 stages. Table 1 shows urinary protein levels at different stages.

Table 1

Urinary protein levels of participants at different stagesa

Parameters	Sampling stages	Group A	Group B	Group C
Total protein (mg/day)	Pre-training1	134.2 ± 0.382	114.2 ± 0.207	123.4 ± 0.316
	Post-training10	156.4 ± 0.618	174.2 ± 0.299
	Post-training11	205.5 ± 0.708	254.2 ± 1.168
	Pre-training2	220.7 ± 0.728	259.4 ± 0.918	145.4 ± 0.382
	Post-training20	248.5 ± 0.696	294.4 ± 1.390
	Post-training21	259.2 ± 0.695	325.7 ± 1.710
Albumin (mg/day)	Pre-training1	83.571 ± 22.977	66 ± 20.363	59.428 ± 8.847
	Post-training10	102.14 ± 24.538	84.142 ± 16.787
	Post-training11	122.43 ± 41.923	110.71 ± 21.899
	Pre-training2	135.57 ± 41.035	128.29 ± 21.187	74.142 ± 11.838
	Post-training20	141.14 ± 35.802	151.71 ± 21.731
	Post-training21	170.43 ± 38.100	178.29 ± 23.956
β2 microglobulin (mg/day)	Pre-training1	0.584 ± 0.083	0.597 ± 0.224	0.598 ± 0.084
	Post-training10	0.764 ± 0.104	0.817 ± 0.187
	Post-training11	1.008 ± 0.304	1.058 ± 0.287
	Pre-training2	1.311 ± 0.275	1.315 ± 0.306	0.81 ± 0.153
	Post-training20	1.482 ± 0.290	1.550 ± 0.412
	Post-training21	1.657 ± 0.290	1.658 ± 0.354
Urinary Protein/Creatinine	Pre-training1	0.444 ± 0.122	0.371 ± 0.069	0.418 ± 0.112
	Post-training10	0.484 ± 0.206	0.513 ± 0.087
	Post-training11	0.563 ± 0.201	0.676 ± 0.353
	Pre-training2	0.571 ± 0.189	0.641 ± 0.239	0.446 ± 0.124
	Post-training20	0.614 ± 0.173	0.674 ± 0.294
	Post-training21	0.613 ± 0.171	0.703 ± 0.321

Values are mean ± SD.

A significant increase in all urinary protein levels (mixed type, predominantly albuminuria) was observed compared to basal levels, particularly following RT program (P = 0.02, 0.001 and 0.002 for total protein, albumin and β2 microglobulin, respectively), without any significant difference between the two experimental groups (all P > 0.05). No microscopic hematuria was detected in urine samples (all in luteal phase). It seems that different types of physical training (resistive, endurance, continuous or intermittent) have no preference each other in urinary protein loss [1], however, some studies oppose this finding [2]. In addition, physical training may have a protective effect against exercise-induced hematuria in untrained and trained females. Undoubtedly, further researches regarding this issue are needed.