Hugh Pinnington

Accuracy and reliability of a Cosmed K4b2 portable gas analysis system

The purpose of this study was to assess the validity and reliability of a Cosmed K4b2 portable telemetric gas analysis system. Twelve physically fit males performed a treadmill running session consisting of an easy 10 min run, a hard 3 min run and a 1 min sprint (with rest periods of 10 min separating each run), on four separate occasions. Sessions were identical with the exception of the apparatus used to measure VO2. During two (test-retest) sessions a Cosmed K4b2 portable gas analysis system was used; in another, a laboratory metabolic cart and, in one session, both systems were used to measure VO2 simultaneously. Comparison of Cosmed K4b2 and metabolic cart measurements in isolation revealed significantly (p < 0.05) increased values of VO2, VCO2, FE CO2 (except FE CO2 at 10 min) and lower values of FE O2 for each run duration by the Cosmed system. Linear regression equations to predict metabolic cart results from Cosmed values were, respectively; cart VO2 = 0.926 (Cosmed VO2-0.227 (r2 = 0.84) and cart VCO2 = 1.057 (Cosmed VCO2-0.606 (r2 = 0.92). Bland-Altman plots and comparison of the test-retest cosmed measurements revealed that the K4b2 system showed good repeatability of measurement for measures of VE, VO2 and VCO2, particularly for 10 min and 3 min tests (ICC = 0.7-0.9, p < 0.05). In conclusion, the Cosmed K4b2 portable gas analysis system recorded consistently higher VO2 and VCO2 measurements in comparison to a metabolic cart. However, satisfactory test-retest reliability of the system was demonstrated.

The level of accuracy and agreement in measures of FEO2, FECO2 and V̇E between the cosmed K4b2 portable, respiratory gas analysis system and a metabolic cart

This study aimed to assess the accuracy of the Cosmed K4b2 (Cosmed, Italy) portable metabolic system that measures FEO2, FECO2 and VE on a breath by breath basis. For gas concentration comparisons, expired air from 20 subjects performing treadmill running was collected in a 600 litre chain compensated Collins Tissot tank and analysed for FEO2 and FECO2 using a laboratory metabolic cart and the Cosmed K4 b2 metabolic system. For ventilation comparisons, serial steady state VE (STPD) values were measured on 10 subjects using the Cosmed K4b2 ventilation turbine and a Morgan ventilation monitor during a continuous treadmill running protocol at ascending speeds of 8, 11 and 14 km x h(-1). The Cosmed K4b2 FEO2 and FECO2 measures were significantly lower (P < 0.001) than the metabolic cart values. Pearson correlation coefficients (r) and the standard error of measurement (SEM) demonstrated a high association between the Cosmed and the metabolic cart measures (FEO2 r =0 .971, SEM 0.071: FECO2 r = 0.925, SEM 0.087). Cosmed VE (l x min(-1)) measures were significantly greater than Morgan values at running speeds of 8 kmh(-1) (P < 0.001) and 11 kmh(-1) (P < 0.001) but not significantly different at 14 km x h(-1) (P > 0.05). When VE measures at the three running speeds were combined, the mean difference between instrument measures ranged between 3.5 - 4.0 l x min(-1) but the values were highly correlated (r= 0.982, P<0.01; SEM 3.03). Linear regression analysis revealed the following regression equations to predict metabolic cart values from Cosmed measures: FEO2 = 0.852+0.963 Cosmed (R2 = 0.940, P<0.00 1), FECO2 = 0.627+0.878 Cosmed (R2=0.856, P<0.001), VE = -2.50+0.984 Cosmed (R2 = 0.965. P < 0.001). The results indicated that the Cosmed K4b2 unit assessed here produced measures of FEO2, FECO2 and VE that had strong correlation to values obtained from a metabolic cart. However, linear regression analysis may further improve the accuracy of Cosmed K4b2 measures when compared to metabolic cart values.

The energy cost of running on grass compared to soft dry beach sand

This study compared the energy cost (EC) (J x kg(-1) x m(-1)) of running on grass and soft dry beach sand. Seven male and 5 female recreational runners performed steady state running trials on grass in shoes at 8, 11 and 14 km x h(-1). Steady state sand runs, both barefoot and in shoes, were also attempted at 8 km x h(-1) and approximately 11 km x h(-1). One additional female attempted the grass and sand runs at 8 km x h(-1) only. Net total EC was determined from net aerobic EC (steady state VO2, VCO2 and RER) and net anaerobic EC (net lactate accumulation). When comparing the surface effects (grass, sand bare foot and sand in shoes) of running at 8 km x h(-1) (133.3 m x min(-1)) in 9 subjects who most accurately maintained that speed (133.3 +/- 2.2 m x min(-1)), no differences (P>0.05) existed between the net aerobic, anaerobic and total EC of sand running barefoot or in shoes, but these measures were all significantly greater (P<0.05) than the corresponding values when running on grass. Similarly, when all running speed trials (n = 87) performed by all subjects (n = 13) for each surface condition were combined for analysis, the sand bare foot and sand in shoes values for net aerobic EC, net anaerobic EC and net total EC were significantly greater (P<0.001) than the grass running measures, but not significantly different (P>0.05) from each other. Expressed as ratios of sand to grass running EC coefficients, the sand running barefoot and sand in shoes running trials at 8 km x h(-1) revealed values of 1.6 and 1.5 for net aerobic EC, 3.7 and 2.7 for net anaerobic EC and 1.6 and 1.5 for net total EC respectively. For all running speeds combined, these coefficients were 1.5 and 1.4 for net aerobic EC, 2.5 and 2.3 for net anaerobic EC and 1.5 and 1.5 for net total EC for sand running barefoot and in shoes respectively. Sand running may provide a low impact, but high EC training stimulus.

Examination of the validity and reliability of the accusport blood lactate analyser

Clough et al. (1997) reported that 95% of lactate values obtained using an Accusport analyser may be up to 2.6 mM below or 2.1 mM above YSI 2300 analyser values over the range 0-16 mM. This variability is substantial and unsuitable for research purposes, The objectives of this study were to re-examine the specific validity and reliability of an Accusport analyser and to develop a regression equation to improve the accuracy of Accusport measurements. Duplicate measurements of lactate concentration were made on both an Accusport (Boehringer Mannheim) and Analox LM3 Multi Channel analyser on 17 blood samples taken from two subjects performing a discontinuous incremental exercise protocol. Analysis of duplicate measurements revealed good test-retest reliability for Accusport (TEM 0.35 mM; SEM 0.24 mM; ICC r = 0.995) and Analox (TEM 0.07 mM; SEM 0.09 mM; ICC r = 0.999). The mean values for duplicate samples recorded on both the Accusport and Analox between the lactate range of 1-13 mM revealed an average difference between the two analysers of 1.7 mM (P< 0.01, range 1.0-2.9 mM) but values demonstrated a high level of association (ICC r = 0.853; P< 0.05). The level of agreement indicated that in 95% of cases the differences would lie between + 0.5 to + 3.0 mM with the Accusport values always higher than Analox. Linear regression analysis calculated the following equation to predict Analox values from Accusport values: Analox = -0.749 + 0.837Accusport (R2 = 0.990). The results showed the portable Accusport analyser to be reliable and it demonstrated good association with Analox LM3 lactate analyser measures. However, a need exists to develop specifically generated regressions from Accusport and Analox LM3 analyser measures to provide more accurate results when interpreting lactate values from Accusport measures taken in the field.

Effect of training surface on acute physiological responses after interval training.

Abstract Binnie, MJ, Dawson, B, Pinnington, H, Landers, G, and Peeling, P. Effect of training surface on acute physiological responses after interval training. J Strength Cond Res 27(4): 1047–1056, 2013—This study compared the effect of sand and grass training surfaces during a common preseason interval training session in well-trained team sport athletes (n = 10). The participants initially completed a preliminary testing session to gather baseline (BASE) performance data for vertical jump, repeated sprint ability, and a 3-km running time trial (RTT). Three days subsequent to BASE, all the athletes completed the first interval training session, which was followed by a repeat of the BASE performance tests the following day (24 hours postexercise). Seven days later, the same interval training session was completed on the opposing surface and was again followed 24 hours later by the BASE performance tests. During each session, blood lactate (BLa), ratings of perceived exertion, and heart rate (HR) were recorded. Additionally, venous blood was collected preexercise, postexercise, and 24 hours postexercise and analyzed for serum concentrations of myoglobin, creatine kinase, haptoglobin, and C-reactive protein. Results showed significantly higher BLa and HR responses experienced during the SAND session (p < 0.05), with no differences observed between surfaces for the blood markers of muscle damage, inflammation, and hemolysis (p > 0.05). Twenty-four hours later, the RTT was performed significantly faster after the SAND session compared with GRASS (p = 0.001). These results suggest that performing interval training on a sand (vs. grass) surface can result in a greater physiological response, without any additional detriment to next day endurance performance.

Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes

Abstract This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P < 0.05) HR and training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P < 0.05) improvements in VO2max were measured for SAND compared to GRASS. These results suggest that substituting sand for grass training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.

Part 2: Effect of training surface on acute physiological responses after sport-specific training

Abstract Binnie, MJ, Dawson, B, Pinnington, H, Landers, G, and Peeling, P. Part 2: Effect of training surface on acute physiological responses after sport-specific training. J Strength Cond Res 27(4): 1057–1066, 2013—This study compared the effect of sand and grass training surfaces during a sport-specific conditioning session in well-trained team sport athletes (n = 10). The participants initially completed a preliminary testing session to gather baseline (BASE) performance data for vertical jump, repeated sprint ability, and 3-km running time trial. Three days subsequent to BASE, all the athletes completed the first sport-specific conditioning session, which was followed by a repeat of the BASE performance tests the following day (24 hours postexercise). Seven days later, the same training session was completed on the opposing surface and was again followed 24 hours later by the BASE performance tests. During each session, blood lactate, ratings of perceived exertion (RPE), and heart rate (HR) were recorded, with player movement patterns also monitored via global positioning system units. Additionally, venous blood was collected preexercise, postexercise, and 24 hours postexercise, and analyzed for serum concentrations of Myoglobin, Haptoglobin, and C-Reactive Protein. Results showed significantly higher HR and RPE responses on SAND (p > 0.05), despite significantly lower distance and velocity outputs for the training session (p > 0.05). There were no differences in 24 hours postexercise performance (p > 0.05), and blood markers of muscle damage, inflammation and hemolysis were also similar between the surfaces (p > 0.05). These results suggest that performing a sport-specific conditioning session on a sand (vs. grass) surface can result in a greater physiological response, without any additional decrement to next-day performance.

Effect of Surface-specific Training on 20-m Sprint Performance on Sand and Grass Surfaces

Abstract Binnie, MJ, Peeling, P, Pinnington, H, Landers, G, and Dawson, B. Effect of surface-specific training on 20-m sprint performance on sand and grass surfaces. J Strength Cond Res 27(12): 3515–3520, 2013—This study compared the effect of an 8-week preseason conditioning program conducted on a sand (SAND) or grass (GRASS) surface on 20-m sprint performance. Twelve team-sport athletes were required to attend three 1-hour training sessions per week, including 2 surface-specific sessions (SAND, n = 6 or GRASS, n = 6) and 1 group session (conducted on grass). Throughout the training period, 20-m sprint times of all athletes were recorded on both sand and grass surfaces at the end of weeks 1, 4, and 8. Results showed a significant improvement in 20-m sand time in the SAND group only (p < 0.05), whereas 20-m grass time improved equally in both training subgroups (p < 0.05). These results suggest that surface-specificity is essential for 20-m speed improvements on sand and also that there is no detriment to grass speed gains when incorporating sand surfaces into a preseason program.

Sand training: Exercise-induced muscle damage and inflammatory responses to matched-intensity exercise

Abstract This study compared markers of muscle damage and inflammation elevated by a matched-intensity interval running session on soft sand and grass surfaces. In a counterbalanced, repeated-measures and crossover design, 10 well-trained female athletes completed 2 interval-based running sessions 1 week apart on either a grass or a sand surface. Exercise heart rate (HR) was fixed at 83–88% of HR maximum. Venous blood samples were collected pre-, post- and 24 h post-exercise, and analysed for myoglobin (Mb) and C-reactive protein (CRP). Perceptual ratings of exertion (RPE) and muscle soreness (DOMS) were recorded immediately post- and 24 h post-exercise. A significant time effect showed that Mb increased from pre- to post-exercise on grass (p = .008) but not on sand (p = .611). Furthermore, there was a greater relative increase in Mb on grass compared with that on sand (p = .026). No differences in CRP were reported between surfaces (p > .05). The HR, RPE and DOMS scores were not significantly different between conditions (p  >  .05). These results suggest that in response to a matched-intensity exercise bout, markers of post-exercise muscle damage may be reduced by running on softer ground surfaces. Such training strategy may be used to minimize musculoskeletal strain while still incurring an equivalent cardiovascular training stimulus.