BACKGROUND: There are alterations in strength in relation to menstrual cycle phase but little data attributing these responses to female sex hormone levels using a pseudo-menstrual cycle group as control. OBJECTIVE: Examining the effects of menstrual cycle phase on the development of peak torque across a range of isokinetic speeds. METHOD: 17 well trained females, 11 formed the non-oral contraceptive group (n-OC) (age 20.7 ± 1.4 yrs, mass 59.2 ± 6.9 kg, height 166.8 ± 7.1 cm) and 6 the oral contraceptive control group (OC) (age 20.3 ± 0.5 yrs, mass 60.5 ± 4.2 kg, height 164.8 ± 4.8 cm). Concentric strength of the knee flexors and extensors (60-240 • /s) was assessed, corresponding to menstruation (MEN), mid-follicular (mFOL), mid-luteal (mLUT) and pre-menstrual (pMEN). RESULTS: For n-OC significant decreases in peak torque production of the extensors at 120 • /s (P = 0.0207) (MEN) and of the flexors at 60 • /s (P = 0.0116) (MEN) and 120 • /s (P = 0.0282) (MEN) were observed compared to pMEN. No significant differences were observed across any menstrual cycle phase and peak torque for the OC group (p > 0.05). Significant positive correlations were observed (mLUT) between peak torque and oestrogen at 60 • /s (P = 0.040) and 120 • /s (P = 0.031). CONCLUSIONS: There are significant fluctuations in peak torque of the knee extensors in response to phases of the menstrual cycle associated with variances in the female sex hormones. The findings have implications for the planning of strength training in female athletes.

PurposeThe aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5–3 h, 3–3.5 h, 3.5–4 h, 4–4.5 h and >4.5 h).Materials and methodsA total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm), with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1), lactate turn point (LT2) and running economy (RE). Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of trueV˙normalO2max. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data.ResultsTraining frequency was shown to be significantly greater for the 2.5–3 h group compared to the 3.5–4 h runners (P < 0.001) and >4.5 h group (P = 0.004), while distance per session (km·session−1) was significantly greater for the 2.5–3 h group (16.1 ± 4.2) compared to the 3.5–4 h group (15.5 ± 5.2; P = 0.01) and >4.5 h group (10.3 ± 2.6; P = 0.001). Race speed correlated with LT1 (r = 0.791), LT2 (r = 0.721) and distance per session (r = 0.563).ConclusionThe data highlight profound differences for key components of marathon running (trueV˙normalO2max, LT1, LT2, RE and % trueV˙normalO2max) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed.

The purpose of this study was to address if there is an association between the plateau at V˙O (2max) and the anaerobic capacity. 9 well-trained cyclists (age 22.2 ± 3.5 yr, height 182.5 ± 5.0 cm, mass 75.7 ± 8.7 kg, V˙O (2max) 59.3 ± 4.8 ml x kg(-1) x min(-1)completed both an incremental step test of 20 W x min(-1) starting at 120 W for determination of maximal oxygen uptake (MOU) and a maximally accumulated oxygen deficit (MAOD) trial at 125% MOU for estimation of anaerobic capacity. Throughout all trials expired air was recorded on a breath-by-breath basis. A significant inverse relationship was observed between the MAOD and the Δ V˙O (2) during the final 60 s of the MOU test (r=-0.77, p=0.008). Of the 9 participants it was noted that only 4 exhibited a plateau at MOU. There were non-significant differences for V˙O (2) and the associated secondary criteria for those exhibiting a plateau and the non-plateau responders, despite a significant difference for MAOD (p=0.041) between groups. These data suggest that incidence of the plateau at MOU is dependent on anaerobic substrate metabolism and that ranges of responses reported in the literature may be a consequence of variations in anaerobic capacity amongst participants.

The purpose of this study was to examine the effect of menstrual cycle phase on maximal oxygen uptake (V˙O2max) and associated cardiodynamic responses. A total of 16 active females volunteered of which n = 10 formed the non-oral contraceptive pill group (n-OCP), displaying a regular menstrual cycle of 28·4 ± 2·2 days (age 20·6 ± 1·6 years, height 169·9 ± 6·4 cm, mass 68·7 ± 7·9 kg) and n = 6 formed the oral contraceptive pill group (OCP) (monophasic pill) (age 21·7 years ± 2·16, height 168·1 cm ± 6·8 cm, mass 61·6 ± 6·8 kg). Each completed four incremental exercise tests for determination of V˙O2max, cardiac output, stroke volume and heart rate. Each test was completed according to the phases of the menstrual cycle as determined through salivary analysis of 17-β oestrodiol and progesterone. Non-significant differences were observed for V˙O2max across phases and between groups (P>0·05) with additional non-significant differences for Q˙max, HR and SV between groups. For ∆ V˙O2 during the final 60 s of the V˙O2max trial, significant differences were observed between OCP and n-OCP (P<0·05) with OCP showing zero V˙O2 plateaus in three pseudo-phases. Significant difference observed for a-vO n-OCP between premenstruation and menstruation at 30-100% V˙O2max (P<0·05). Data suggest that the V˙O2 -plateau is effected by monophasic oral contraceptive pill, furthermore these data imply that V˙O2max test outcome is independent of menstrual cycle phase but caution should be applied when evaluating maximal oxygen uptake in females who are administered a monophasic oral contraceptive pill.

The purpose of this study was to determine the effect of 6 min of prior-priming exercise on the incidence of plateau at VO(2max). Twelve trained cyclists (age, 21 ± 3 years; height, 175·0 ± 8·0 cm; weight, 69·0 ± 10·4 kg; maximal oxygen uptake (VO(2max)), 56·3 ± 6·9 ml kg(-1) min(-1)) completed three incremental tests to volitional exhaustion, which were classified as unprimed (UP), heavy-primed (HP) and severe-primed (SP), at a work rate of 1 W 2 s(-1), from an initial workload of 100 W, for the determination of VO(2max). VO(2max) trial in the HP and SP conditions was preceded by a period of 4-min unloaded cycling followed by a further 6 min of constant load cycling at Δ50% VO(2) gas exchange threshold (GET)-VO(2max) (HP) and Δ75% VO(2) GET-VO(2max) (SP). Expired air was recorded on a breath-by-breath basis during all trials. The criteria adopted for a plateau in VO(2max) was a ΔVO(2) over the final two consecutive 30-s sampling periods ≤ 2·1 ml kg(-1) min(-1). There was a significant increase in plateau responses between the UP (50%) and HP (100%) conditions (P = 0·001) coupled with a significant change in the slope of the regression line during the final 60 s of the VO(2max) test, UP and HP (P = 0·0299) and UP and SP (P = 0·0296). These data suggest that a bout of prior-priming exercise promotes an increased incidence of plateau responses at VO(2max) . It is suggested that future studies address how such an approach can be adopted without prior knowledge of GET.

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The purpose of this study was to determine the effects of a reduced whole body blood volume on the kinetic response of VO(2) during moderate and heavy intensity exercise. Six males and four females (age, 21+/-2 yrs; height, 175.2+/-5.1 cm; weight, 66.4+/-2.8 kg; VO(2)max, 53.0+/-4.1 ml x kg (-1) x min(-1)), completed a square-wave cycling ramp test to determine ventilatory threshold (VT) and VO(2max). Kinetics trials were completed 24 h pre and post donation of 450 cm (3) of blood. The kinetics trials were moderate intensity (80%VT) and heavy intensity (Delta50% VT - VO(2max)). Breath-by-breath gas exchange, heart rate, blood pressure, haemoglobin O(2) saturation, and blood [lactate] were measured throughout the trials. Post-donation haemoglobin, haematocrit and erythrocyte count were all significantly reduced (por= 0.05), or in the amplitude of the slow component. The capacity of the cardiovascular system to meet the metabolic demands of skeletal muscle at the onset of exercise does not limit the oxygen uptake.