257
Exercise Training at and above the Lactate Threshold in Previously Untrained Women A. Weitman, R. L. Seip, D. Snead, J. Y Weitman, E. M Haskvitz, W. S. Evans, J. D. Veidhuis, A. D. Rogol Exercise Physiology Laboratory (AW, RLS, DS, EMH), Curry School of Education, and Departments of Pediatrics (JYW, ADR), Pharmacology (ADR), Internal Medicine (AW, WSE, JDV), Health Sciences Center; The Biodynamics Institute (WSE, JDV, ADR); and Interdisciplinary Graduate Biophysics Program (JDV), University of Virginia, Charlottesville, VA 22903
A. Weitman, R. L. Seip, D. Snead, J. Y. Weltman, E. M Haskvitz, W. S. Evans, J. D. Veidhuis and A. D.
Rogol, Exercise Training at and above the Lactate Threshold in Previously Untrained Women. mt j Sports Med, Vol 13,No3,pp257—263, 1992.
cantly higher values than the C and @ LT groups for LT (p < 0.05). For FBLC of 2.0, 2.5, and 4.0mM and Max, the
> LT group values were greater than the C group (p LT group had higher V02 and V Max values than the @ LT group after training, these differences were not statistically significant. An interaction was observed with the increase in VO2 and V
Accepted after revision: October 30, 1991
in the > LT group being greater than the @ LT and C groups for LT and FBLC of 2.0, 2.5, and 4.0 mM and
We examined the effects of training at and
greater than the C group for Max (p < 0.05). Within group analysis revealed that both training groups showed similar
above the lactate threshold in previously untrained women.
Twenty-four untrained eumenorrheic women (age =
increases in V02 and V at LT, FBLC of 2.0 and 2.5mM from
31.3±4.0 yrs, wt=66.2±7.6 kg, ht=166.4±5.8 cm)
baseline to MC 4 (p LT group continued to increase 'O2 and V with no further
were assessed at baseline [during days 1—3 of the menstrual cycle (MC) ii and every 4 MC after that (for 1 year) for V02
and velocity (V) at LT, fixed blood lactate concentrations (FBLC) of 2.0, 2.5, and 4.0 mM, and Max. Subjects were assigned to control (C, n = 7), at LT @ LT, trained 6 days/ week at the velocity associated with LT, n =9) or above LT
(>LT, trained 3 days/week at the velocity midway between V LT and V Max and 3 days/week at V LT, n =8) groups. Exercise prescriptions were adjusted after each assessment and each group progressed similarly in weekly mileage. No between group differences were observed before training. After training the > LT group had signifi-
change observed in the @ LT group (p LT, n = 8), and at the lactate threshold (@ LT, n =9). Seven subjects
stage of the V02 peak protocol from an indwelling venous
served as a control group (C). Physiological parameters were
assessed during the early follicular phase of the menstrual cycle at baseline and every 4th menstrual cycle after that for the
remainder of the 12—14 months of training in the @ LT and > LT groups. The control group was assessed at baseline and 12—14 months after baseline. Measurements of the lactate threshold, fixed blood lactate concentrations, peak oxygen uptake, maximal oxygen uptake, and body composition were made at each assessment.
VO2max VO2max was determined using an inclined treadmill protocol. The treadmill velocity remained constant at 140 rn/mm, beginning at 0% grade, with an increase in percent grade of 2.5% every 2 minutes. Subjects were given verbal
encouragement throughout the test and the test was terminated when the subject would not complete a given work load. VO2max was chosen as the highest 1 mm oxygen uptake attained during the test.
V02 Peak V02 peak was determined using a continuous, horizontal walk/run treadmill protocol (28). The initial treadmill velocity was 60 rn/mm. Each subsequent 3-mm stage was increased by 10 rn/mm. Subjects were given verbal encouragement throughout the test and the test was terminated when the subject would not complete a given work load. V02 peak was chosen as the highest 1 mm oxygen uptake attained during the test. The highest value attained (from either the VO2max or V02 peak protocols) was used as VO2max in the data analysis. A minimum of 24 hours elapsed between VO2max and V02 peak protocols.
catheter located in the back of the hand. Subjects continued to
run during blood sampling while resting their hands on the rails of the treadmill. A heparinized saline solution was infused after each blood sample to prevent clotting. Whole blood samples were analyzed immediately for lactate concentration with an automated lactate analyzer (Yellow Springs Instruments Model 23L).
The lactate threshold was determined by examining the blood lactate-velocity relationship observed during the V02 peak test (28). The highest velocity attained that was not associated with an elevation in blood lactate concentration above baseline was designated as the velocity associated with lactate threshold (V LT). This always occurred just before the curvilinear increase in blood lactate observed with subsequent exercise intensities. A lactate elevation of at least 0.2 mM (the error associated with the lactate analyzer) was required for LT determination. V02 corresponding to V LT (from individual plots of V02 vs velocity) was designated as the V02 associated with the lactate threshold (VO2 LT) and the heart rate at this velocity was defined as the heart rate associated with lactate threshold (HR-LT). Velocities associated with fixed blood lactate concentrations of 2.0 mM 2.5 mM, and 4.0mM were determined from the curvilinear rise in blood lactate observed from the velocity-blood lactate relationship. V02 and HR values associated with fixed blood lactate concentrations were determined in a manner identical with that described for LT (28). LT and FBLC were all assessed because of the differing opinions regarding the most appropriate level
of blood lactate for predicting endurance performance and/or prescribing training intensity (1, 12, 15, 33).
Body Composition Percent body fat was assessed by hydrostatic weighing (13). Each subject was weighed in air on an Accu-
Weigh beam scale accurate to 0.1 kg and subsequently weighed underwater on a Chatillon autopsy scale accurate to 50 g. Residual volume was measured using the oxygen dilution technique described by Wilmore (32). The computational pro-
Downloaded by: Universite de Sherbrooke. Copyrighted material.
258 mt. J. Sports Med. 13(1992)
mt. J. Sports Med. 13(1992) 259
L Tfor Exercise Prescription
Table 1 Pre- and Post-Training V02 LT,V02 at FBLC of 2.0, 2.5, and 4.0 mM, (ml/kgmin1), and body composition parameters.
Control Group
@
> LT group
LT group
(n=9)
(n=7)
(n =8)
Pre X (SD)
Post X (SD)
Pre X (SD)
Post X (SD)
Pre X (SD)
Post X (SD)
Max
24.2 (6.4) 31.2 (6.1) 33.4 (6.7) 37.0 (7.9) 40.9 (9.3)
24.5 (6.5) 30.0 (6.1) 31.9 (6.6) 35.8 (7.4) 40.6 (8.4)
23.3 (4.3) 30.7 (5.1) 32.8 (5.4) 38.0 (5.6) 42.7 (6.2)
29.7 (6.9) 36.0 (5.9) 37.9 (5.8) 42.0 (5.8) 47.4 (8.0)
26.2 (6.9) 32.6 (6.3) 34.7 (6.4) 39.1 (6.4) 44.2 (5.5)
36.6 (3.4) 41.8 (4.1) 43.3 (4.2) 46.9 (2.1) 50.1 (4.6)
% Body Fat FatWt. (kg) Lean Wt. (kg)
31.8 (5.6) 21.4 (7.9) 46.0 (3.2)
30.3 (7.3) 20.6 (6.6) 46.3 (2.7)
29.2 (3.3) 20.0 (5.2) 47.6 (5.8)
28.7 (3.3) 19.7 (5.0) 48.4 (6.1)
27.4 (6.6) 18.1 (5.6) 46.9 (3.1)
25.9 (4.5) 16.7 (3.8) 47.5 (3.3)
Variable
V02 LT
2.0 mM 2.5 mM 4.0 mM
1) Both @ LT and > LT groups had higher V02 at LT, FBLC of 2.0, 2.5, and 4.0 mM, and Max after one year of training (p LT group had a greater V02 at LT post-training than the @ LT group (p LT group was greater than the increase observed in the @ LT group (p LT group trained three times per week at the velocity corresponding to their individual LT (± 10 m/min). The > LT group also trained three times per week above their LT velocity, at the velocity corresponding to the midpoint between the velocity at
LI and maximal velocity (± 10 m/min, as determined from the LT/Peak test). Up to one half the weekly mileage, not to exceed five miles per session (fifteen miles per week), was covered at this pace. The @ LT group trained six times per week at a pace that corresponded to their velocity at LT (± 10 rn/mm). Subjects were supervised on an outdoor track three times per week (the > LI subjects were always supervised on their > LT training days). During these supervised sessions the training pace was monitored and subjects were provided feedback about their training pace and corrections were made as required. Training logs were maintained during the non supervised days. The control group did not engage in any run training. Training paces were adjusted after each physiological evaluation (i. e., every fourth menstrual cycle) to reflect training changes that may have occurred.
Statistical Analysis Data were analyzed using a two-way analysis of variance with repeated measures (groups x time with repeated measures over time). An alpha level of p = 0.05 was
chosen a priori. When mean differences were observed, post hoc comparisons were made using the General Linear Models Procedure using the Least Squares Means (SAS 5.18, Cary, N. C., 1985). Results
Table 1 presents the oxygen uptake values at LI, FBLC of 2.0, 2.5, and 4.0 mM, and Max before and after one year of training in the C, @ LT and > LT groups. For V02 LT no between group differences were observed before training. After training the > LT group had a significantly higher V02 LT value compared to the @ LT and C groups (p LT baseline
cycle 4 cycle 8 cycles of training (c)
cyclel2
cycles of training
40
cycle 12
baseline
cycle 4 cycle 8 cycles of trainIng
cycle 12
(d)
60 55
—
I baseline
--So-- @LI > LT
cycle 4 cycle8 cycles of training
cyclel2
(e)
Fig. 1 Time course (every fourth menstrual cycle) of adaptation to training in oxygen uptake values at LI (a), FBLC of 2.0 (b), 2.5 (c), and 4.0 mM (d), and Max (e) in the @ LI and — LI groups. Both groups improved similarly from baseline to cycle 4. From cycle 4 to cycle 12 the > LT group showed continued improvement. Vertical bars represent SEM.
No differences were observed for VO2max after training between the @ LT and C groups or between the @ LT and
Exercise Training at and above the Lactate Threshold in Previously Untrained Women A. Weitman, R. L. Seip, D. Snead, J. Y Weitman, E. M Haskvitz, W. S. Evans, J. D. Veidhuis, A. D. Rogol Exercise Physiology Laboratory (AW, RLS, DS, EMH), Curry School of Education, and Departments of Pediatrics (JYW, ADR), Pharmacology (ADR), Internal Medicine (AW, WSE, JDV), Health Sciences Center; The Biodynamics Institute (WSE, JDV, ADR); and Interdisciplinary Graduate Biophysics Program (JDV), University of Virginia, Charlottesville, VA 22903
A. Weitman, R. L. Seip, D. Snead, J. Y. Weltman, E. M Haskvitz, W. S. Evans, J. D. Veidhuis and A. D.
Rogol, Exercise Training at and above the Lactate Threshold in Previously Untrained Women. mt j Sports Med, Vol 13,No3,pp257—263, 1992.
cantly higher values than the C and @ LT groups for LT (p < 0.05). For FBLC of 2.0, 2.5, and 4.0mM and Max, the
> LT group values were greater than the C group (p LT group had higher V02 and V Max values than the @ LT group after training, these differences were not statistically significant. An interaction was observed with the increase in VO2 and V
Accepted after revision: October 30, 1991
in the > LT group being greater than the @ LT and C groups for LT and FBLC of 2.0, 2.5, and 4.0 mM and
We examined the effects of training at and
greater than the C group for Max (p < 0.05). Within group analysis revealed that both training groups showed similar
above the lactate threshold in previously untrained women.
Twenty-four untrained eumenorrheic women (age =
increases in V02 and V at LT, FBLC of 2.0 and 2.5mM from
31.3±4.0 yrs, wt=66.2±7.6 kg, ht=166.4±5.8 cm)
baseline to MC 4 (p LT group continued to increase 'O2 and V with no further
were assessed at baseline [during days 1—3 of the menstrual cycle (MC) ii and every 4 MC after that (for 1 year) for V02
and velocity (V) at LT, fixed blood lactate concentrations (FBLC) of 2.0, 2.5, and 4.0 mM, and Max. Subjects were assigned to control (C, n = 7), at LT @ LT, trained 6 days/ week at the velocity associated with LT, n =9) or above LT
(>LT, trained 3 days/week at the velocity midway between V LT and V Max and 3 days/week at V LT, n =8) groups. Exercise prescriptions were adjusted after each assessment and each group progressed similarly in weekly mileage. No between group differences were observed before training. After training the > LT group had signifi-
change observed in the @ LT group (p LT, n = 8), and at the lactate threshold (@ LT, n =9). Seven subjects
stage of the V02 peak protocol from an indwelling venous
served as a control group (C). Physiological parameters were
assessed during the early follicular phase of the menstrual cycle at baseline and every 4th menstrual cycle after that for the
remainder of the 12—14 months of training in the @ LT and > LT groups. The control group was assessed at baseline and 12—14 months after baseline. Measurements of the lactate threshold, fixed blood lactate concentrations, peak oxygen uptake, maximal oxygen uptake, and body composition were made at each assessment.
VO2max VO2max was determined using an inclined treadmill protocol. The treadmill velocity remained constant at 140 rn/mm, beginning at 0% grade, with an increase in percent grade of 2.5% every 2 minutes. Subjects were given verbal
encouragement throughout the test and the test was terminated when the subject would not complete a given work load. VO2max was chosen as the highest 1 mm oxygen uptake attained during the test.
V02 Peak V02 peak was determined using a continuous, horizontal walk/run treadmill protocol (28). The initial treadmill velocity was 60 rn/mm. Each subsequent 3-mm stage was increased by 10 rn/mm. Subjects were given verbal encouragement throughout the test and the test was terminated when the subject would not complete a given work load. V02 peak was chosen as the highest 1 mm oxygen uptake attained during the test. The highest value attained (from either the VO2max or V02 peak protocols) was used as VO2max in the data analysis. A minimum of 24 hours elapsed between VO2max and V02 peak protocols.
catheter located in the back of the hand. Subjects continued to
run during blood sampling while resting their hands on the rails of the treadmill. A heparinized saline solution was infused after each blood sample to prevent clotting. Whole blood samples were analyzed immediately for lactate concentration with an automated lactate analyzer (Yellow Springs Instruments Model 23L).
The lactate threshold was determined by examining the blood lactate-velocity relationship observed during the V02 peak test (28). The highest velocity attained that was not associated with an elevation in blood lactate concentration above baseline was designated as the velocity associated with lactate threshold (V LT). This always occurred just before the curvilinear increase in blood lactate observed with subsequent exercise intensities. A lactate elevation of at least 0.2 mM (the error associated with the lactate analyzer) was required for LT determination. V02 corresponding to V LT (from individual plots of V02 vs velocity) was designated as the V02 associated with the lactate threshold (VO2 LT) and the heart rate at this velocity was defined as the heart rate associated with lactate threshold (HR-LT). Velocities associated with fixed blood lactate concentrations of 2.0 mM 2.5 mM, and 4.0mM were determined from the curvilinear rise in blood lactate observed from the velocity-blood lactate relationship. V02 and HR values associated with fixed blood lactate concentrations were determined in a manner identical with that described for LT (28). LT and FBLC were all assessed because of the differing opinions regarding the most appropriate level
of blood lactate for predicting endurance performance and/or prescribing training intensity (1, 12, 15, 33).
Body Composition Percent body fat was assessed by hydrostatic weighing (13). Each subject was weighed in air on an Accu-
Weigh beam scale accurate to 0.1 kg and subsequently weighed underwater on a Chatillon autopsy scale accurate to 50 g. Residual volume was measured using the oxygen dilution technique described by Wilmore (32). The computational pro-
Downloaded by: Universite de Sherbrooke. Copyrighted material.
258 mt. J. Sports Med. 13(1992)
mt. J. Sports Med. 13(1992) 259
L Tfor Exercise Prescription
Table 1 Pre- and Post-Training V02 LT,V02 at FBLC of 2.0, 2.5, and 4.0 mM, (ml/kgmin1), and body composition parameters.
Control Group
@
> LT group
LT group
(n=9)
(n=7)
(n =8)
Pre X (SD)
Post X (SD)
Pre X (SD)
Post X (SD)
Pre X (SD)
Post X (SD)
Max
24.2 (6.4) 31.2 (6.1) 33.4 (6.7) 37.0 (7.9) 40.9 (9.3)
24.5 (6.5) 30.0 (6.1) 31.9 (6.6) 35.8 (7.4) 40.6 (8.4)
23.3 (4.3) 30.7 (5.1) 32.8 (5.4) 38.0 (5.6) 42.7 (6.2)
29.7 (6.9) 36.0 (5.9) 37.9 (5.8) 42.0 (5.8) 47.4 (8.0)
26.2 (6.9) 32.6 (6.3) 34.7 (6.4) 39.1 (6.4) 44.2 (5.5)
36.6 (3.4) 41.8 (4.1) 43.3 (4.2) 46.9 (2.1) 50.1 (4.6)
% Body Fat FatWt. (kg) Lean Wt. (kg)
31.8 (5.6) 21.4 (7.9) 46.0 (3.2)
30.3 (7.3) 20.6 (6.6) 46.3 (2.7)
29.2 (3.3) 20.0 (5.2) 47.6 (5.8)
28.7 (3.3) 19.7 (5.0) 48.4 (6.1)
27.4 (6.6) 18.1 (5.6) 46.9 (3.1)
25.9 (4.5) 16.7 (3.8) 47.5 (3.3)
Variable
V02 LT
2.0 mM 2.5 mM 4.0 mM
1) Both @ LT and > LT groups had higher V02 at LT, FBLC of 2.0, 2.5, and 4.0 mM, and Max after one year of training (p LT group had a greater V02 at LT post-training than the @ LT group (p LT group was greater than the increase observed in the @ LT group (p LT group trained three times per week at the velocity corresponding to their individual LT (± 10 m/min). The > LT group also trained three times per week above their LT velocity, at the velocity corresponding to the midpoint between the velocity at
LI and maximal velocity (± 10 m/min, as determined from the LT/Peak test). Up to one half the weekly mileage, not to exceed five miles per session (fifteen miles per week), was covered at this pace. The @ LT group trained six times per week at a pace that corresponded to their velocity at LT (± 10 rn/mm). Subjects were supervised on an outdoor track three times per week (the > LI subjects were always supervised on their > LT training days). During these supervised sessions the training pace was monitored and subjects were provided feedback about their training pace and corrections were made as required. Training logs were maintained during the non supervised days. The control group did not engage in any run training. Training paces were adjusted after each physiological evaluation (i. e., every fourth menstrual cycle) to reflect training changes that may have occurred.
Statistical Analysis Data were analyzed using a two-way analysis of variance with repeated measures (groups x time with repeated measures over time). An alpha level of p = 0.05 was
chosen a priori. When mean differences were observed, post hoc comparisons were made using the General Linear Models Procedure using the Least Squares Means (SAS 5.18, Cary, N. C., 1985). Results
Table 1 presents the oxygen uptake values at LI, FBLC of 2.0, 2.5, and 4.0 mM, and Max before and after one year of training in the C, @ LT and > LT groups. For V02 LT no between group differences were observed before training. After training the > LT group had a significantly higher V02 LT value compared to the @ LT and C groups (p LT baseline
cycle 4 cycle 8 cycles of training (c)
cyclel2
cycles of training
40
cycle 12
baseline
cycle 4 cycle 8 cycles of trainIng
cycle 12
(d)
60 55
—
I baseline
--So-- @LI > LT
cycle 4 cycle8 cycles of training
cyclel2
(e)
Fig. 1 Time course (every fourth menstrual cycle) of adaptation to training in oxygen uptake values at LI (a), FBLC of 2.0 (b), 2.5 (c), and 4.0 mM (d), and Max (e) in the @ LI and — LI groups. Both groups improved similarly from baseline to cycle 4. From cycle 4 to cycle 12 the > LT group showed continued improvement. Vertical bars represent SEM.
No differences were observed for VO2max after training between the @ LT and C groups or between the @ LT and
