Adrian Scruton

The effects of menstrual cycle phase on the development of peak torque under isokinetic conditions

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.

Pacing accuracy during an incremental step test in adolescent swimmers.

To assess pacing accuracy in a group of adolescent swimmers during an incremental step test. Fifteen well-trained swimmers (age 15±1.5 years; height 170.2±8.8 cm; mass 60.2±6.6 kg), completed two 7×200 m tests, separated by ~72 hours. They swam to a predetermined incrementally increasing pace per step and were instructed to swim at even pace. Upon completion of each step, rating of perceived exertion, heart rate and blood lactate were recorded. Significant differences observed for both trials between actual and predicted swim time (P<0.05). Significant differences also observed between the first and second 100 m of each step in trial 1 for step 1 (P=0.001, effect size [ES] =0.54), step 2 (P=0.0001, ES =0.57), step 4 (P=0.0001, ES =0.53), step 5 (P=0.005, ES =0.65), step 6 (P=0.0001, ES =0.50), and step 7 (P=0.0001, ES =0.70). Similar responses witnessed for trial 2 (P<0.05). Findings suggest that the finite anaerobic capacity was engaged sooner than would normally be anticipated, as a function of an inability to regulate pace. This is proposed to be a consequence of the volume of exposure to the biological and psychological sensations and cognitive developmental status. Given the apparent error in pacing judgment exhibited in this population group, caution should be applied when adopting such tests to monitor training responses with adolescent athletes, and alternate means of modulating pace be investigated.

The effects of menstrual cycle phase on the incidence of plateau at V˙O2max and associated cardiorespiratory dynamics

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 , HRmax and SVmax 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‐vO2dif 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.

Physiological and training characteristics of recreational marathon runners

Purpose The 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 methods A 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 V˙O2max. 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. Results Training 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). Conclusion The data highlight profound differences for key components of marathon running (V˙O2max, LT1, LT2, RE and % V˙O2max) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed.

Pace Versus Prediction: Is the Age of the Runner Associated With Marathon Success?

PURPOSE: The ability to regulate effort (pace) is ascribed to the ability to make prospective judgments regarding the metabolic demands of the exercise challenge against personal metabolic capacity. Thus pace modulations which are dependent on knowing an exercise end-point are a function of biologically and cognitively orchestrated afferent signals and the homeostatically orientated efferent responses are manifest to prevent a depletion of the finite anaerobic capacity and onset of fatigue. The purpose of this study was to examine the pacing strategies adopted during a marathon and to explore whether there was a difference in outcome between males and females. METHOD: Following local institutional ethical approval n= 777 runners competing in the 2015 London Marathon volunteered and agreed to participate of which n= 393 were females and n= 384 were males. Using an online survey, available for 12 weeks up to the marathon and opportunistic sampling at the pre-marathon registration, participants were also asked to predict race time. Additional information regarding age and experience (number of marathons) were also obtained. Prediction time (PT) served as a proxy of end target time. For each participant 5km splits and finish time (FT) were converted to speed and then normalised (%) to the final split time/speed (m.s-1). RESULTS: A significant difference (P= 0.0001) of 476s was observed between PT and FT for the whole group compared to differences of 531 s (p= 0.000) and 419s (P= 0.000) for the males and females respectively. Both males (P= 0.0001) and females (P= 0.0001) showed significant differences between PT and FT. Males exhibited differences in pace for all 5km splits (P= 0.0001) except 5-10km (P= 0.483), large ES between 25-30km (r= 0.319) and 30-35km (r= 0.426), pace decreased from 107.4 ± 7.8% (5km) to 91.2 ± 7.1% (40km), compared to 109.1 ± 8.6% (5km) to 93.2 ± 6.5% (40km) for females. Females exhibited differences across all 5km splits (P= 0.0001) except between 35-40km (P= 1.000) with medium ES for 20-25km (r= 0.243) and 30-35km (r= 0.313). CONCLUSIONS: There is no difference between male and female marathon pacing strategies suggesting that the pacing template is not sex specific. Furthermore these data lend support to the notion that there is not an unfair advantage for females to be paced or race with males.

Pace Versus Prediction: Is the Experience of the Runner Associated With Marathon Success?: 1667 Board #320 June 2, 8: 00 AM - 9: 30 AM.

PURPOSE: Pacing strategies during exercise are attributed to optimising the balance between the artefacts of fatigue and regulation of substrate metabolism. Pace judgement is set within a continuum of information from the ability to anticipate metabolic demands and select an appropriate strategy through to the accumulation of prior experience for completion of such a task that has a known end-point. Therefore the purpose of this study was to evaluate the importance of athlete experience to successfully regulate pace and attain a predicted end time during a marathon. METHOD: Following local institutional ethical approval n= 777 runners competing in the 2015 London Marathon agreed to participate. Using an on-line survey and opportunistic questionnaire at a pre-marathon event participants were asked to predict their race time. Athlete experience (EXP) was established based on the number of previously completed marathons using a Likert scale from 0 to greater than 10 with increments of 1 race. Athlete age was also recorded. All race data was downloaded from the race website generating 5Km split times, then converted to speed and normalised (%) to the final split time/speed (m.s-1). Prediction time (PT) was used a proxy for end-point and compared to finish time (FT). RESULTS: FT for whole group (WG) was 15479 ±3311s compared to the group PT 15003 ±2972s a significant difference of 476s (P= 0.0001). An R2of 0.863 observed for WG compared to 0.799 (EXP-0) and 0.852 (EXP-5) when comparing FT to PT. Significant differences observed between PT and FT for all EXP groups apart from EXP-5 (P= 0.0001). EXP-0 showed significant difference across all split times apart from 35-40 km (P=0.0001) with a decrease in normalised speed from 5km (109.0 ±7.6) –40km (89.9 ±7.4%). The EXP-5 group showed significant changes in pace between 25-30 km (P= 0.001) (ES= 0.35) and 30-35 km (P= 0.0001) (ES= 0.44), decrease in pace from 5km (105.0 ±5.7%) to 40km (93.7 ±5.6%). CONCLUSIONS: These data suggest that successful marathon pacing is dependent on the experience of the athlete reflecting the development of the pacing template. Additionally experience is associated with better attainment of prediction time suggesting that less experienced runners should run with more experienced athletes with similar end-point targets.

A Time-Motion Analysis of Lightweight Women’s Judo in the 2010 World Championships

The Olympic sport of judo has a growing base of performance analysis research considering the technical aspects, the tactical aspects and time motion analysis. This study aimed to further analyse this sport by specifically considering the time motion aspects of work, rest, kumi-kata and ne-waza in lightweight womens judo to establish if there are differences in this specific population of judo athletes. Pre-recorded footage of the womens u48kg, u52kg and u57kg weight divisions (143 contests) from the 2010 world judo championships were coded into temporal sequences. The coding of five KPIs across the three weight groups produced a total of 1756 hajime to matte blocks (work), 1422 matte to hajime blocks (rest), 1786 kumi-kata sequences (gripping sequences), and 516 ne-waza sequences (ground work). The results suggest the time spent in hajime to matte (work) and in matte to hajime (rest) are similar to those seen in other studies. This suggests there is little difference in the work to rest segments for lightweight womens judo compared to heavier weights and males.