Effects of Cycling Intensity on Acute Signaling Adaptations to 8-weeks Concurrent Training in Trained Cyclists.

This study examined whether the intensity of endurance stimuli modifies the adaptation in strength and endurance following concurrent training and whether the acute molecular response to concurrent exercise is affected by training status. Using a parallel group design, trained cyclists were randomized to either resistance exercise followed by moderate intensity continuous training (RES + MICT, n = 6), or resistance exercise followed by work matched high intensity interval training (RES + HIIT, n = 7), across an 8 weeks training programme. A single RES + MICT or RES + HIIT exercise stimulus was completed 1 week before and within 5 days of completing the training programme, to assess phosphorylation of protein kinases of the mTOR and AMPK signaling pathways. There were no main effects of time or group on the phosphorylation of protein kinases in response to concurrent exercise stimulus pre- and post-training intervention (p > 0.05). Main effects of time were observed for all maximal strength exercises; back-squat, split-squat, and calf-raise (p < 0.001), with all improving post intervention. A time × group interaction was present for V̇O2peak, with the RES + MICT group displaying a preferential response to that of the RES + HIIT group (p = 0.010). No time nor group effects were observed for 5 min time trial performance, power at 2 and 4 mmol L-1 (p > 0.05). Whilst preliminary data due to limited sample size the intensity of endurance activity had no effect on performance outcomes, following concurrent training. Further, the acute molecular response to a concurrent exercise stimulus was comparable before and after the training intervention, suggesting that training status had no effect on the molecular responses assessed.

Aerobic exercise intensity does not affect the anabolic signaling following resistance exercise in endurance athletes.

This study examined whether intensity of endurance stimulus within a concurrent training paradigm influenced the phosphorylation of signaling proteins associated with the mTOR and AMPK networks. Eight male cyclists completed (1) resistance exercise (RES), 6 × 8 squats at 80% 1-RM; (2) resistance exercise and moderate intensity cycling of 40 min at 65% V̇O2peak, (RES + MIC); (3) resistance exercise and high intensity interval cycling of 40 min with 6 alternating 3 min intervals of 85 and 45% V̇O2peak (RES + HIIC), in a cross-over design. Muscle biopsies were collected at rest and 3 h post-RES. There was a main effect of condition for mTORS2448 (p = 0.043), with a greater response in the RES + MIC relative to RES condition (p = 0.033). There was a main effect of condition for AMPKα2T172 (p = 0.041), with a greater response in RES + MIC, relative to both RES + HIIC (p = 0.026) and RES (p = 0.046). There were no other condition effects for the remaining protein kinases assessed (p > 0.05). These data do not support a molecular interference effect in cyclists under controlled conditions. There was no intensity-dependent regulation of AMPK, nor differential activation of anabolism with the manipulation of endurance exercise intensity.

Influence of tart cherry juice on indices of recovery following marathon running.

This investigation determined the efficacy of a tart cherry juice in aiding recovery and reducing muscle damage, inflammation and oxidative stress. Twenty recreational Marathon runners assigned to either consumed cherry juice or placebo for 5 days before, the day of and for 48 h following a Marathon run. Markers of muscle damage (creatine kinase, lactate dehydrogenase, muscle soreness and isometric strength), inflammation [interleukin-6 (IL-6), C-reactive protein (CRP) and uric acid], total antioxidant status (TAS) and oxidative stress [thiobarbituric acid reactive species (TBARS) and protein carbonyls] were examined before and following the race. Isometric strength recovered significantly faster (P=0.024) in the cherry juice group. No other damage indices were significantly different. Inflammation was reduced in the cherry juice group (IL-6, P<0.001; CRP, P<0.01; uric acid, P<0.05). TAS was ~10% greater in the cherry juice than the placebo group for all post-supplementation measures (P<0.05). Protein carbonyls was not different; however, TBARS was lower in the cherry juice than the placebo at 48 h (P<0.05). The cherry juice appears to provide a viable means to aid recovery following strenuous exercise by increasing total antioxidative capacity, reducing inflammation, lipid peroxidation and so aiding in the recovery of muscle function.

The influence of cold water immersions on adaptation following a single bout of damaging exercise.

The aim of this investigation was to elucidate the effects of cold water immersions (CWIs) following damaging exercise on the repeated bout effect (RBE). Sixteen males performed two bouts of drop jump exercise separated by 14-21 days. Participants were equally, but randomly assigned to either a CWI (12-min CWI at 15 degrees C) or control group (12-min seated rest). Treatments were given immediately after the first exercise bout, 24, 48 and 72 h post-exercise. No interventions were given following the second bout. Maximum voluntary contraction (MIVC), soreness (DOMS), creatine kinase (CK), thigh girth and range of motion (ROM) were recorded before and for 96 h following the initial and repeated bouts of damaging exercise. All variables, except ROM, showed a significant time effect (P < 0.01) indicating the presence of muscle damage following the initial bout; there were no differences between the CWI and control groups after the initial bout. Following the repeated bout of exercise there was a significant attenuation in the reduction of MIVC (P = 0.002) and a reduction in DOMS (P < 0.001), which is indicative of the RBE. There were no significant differences between groups following the repeated bout of damaging exercise. These data show that CWI had no effect following damaging exercise and did not inhibit the RBE. Despite CWI being used routinely, its efficacy remains unclear and there is a need to elucidate the benefits of this intervention on recovery and adaptation to provide practitioners with evidence based practice.

Evidence of a contralateral repeated bout effect after maximal eccentric contractions.

The aim of this investigation was firstly, to examine whether a contralateral repeated bout effect is manifested after a single bout of maximal eccentric muscle actions and secondly, to compare the magnitude of any such protection to an ipsilateral control. Sixteen male subjects undertook 45 repetitions of maximal eccentric contractions of the elbow flexors. The ipsilateral group (IL, N=8) repeated the exercise using the same arm and the contralateral group (CL, N=8) repeated the exercise using the contralateral arm 14 days later. Serum creatine kinase (CK), muscle soreness, maximal voluntary contraction (MVC) and range of motion (ROM) were significantly attenuated in the repeated bout for IL. CL also showed a significant reduction in the repeated bout for CK, muscle soreness and MVC. Despite the significant attenuation of dependent variables in both groups the magnitude of change was less in CL compared to IL for CK, soreness, MVC and ROM. The findings demonstrate a repeated bout effect in the contralateral limb after a single bout of maximal eccentric exercise; however, the magnitude of protection in the contralateral limb is less than that manifested in the ipsilateral limb. The apparent contralateral repeated bout effect observed in this investigation is thought to be predominantly mediated by neural mechanisms, although further research is required to elucidate this possibility.

The efficacy of ice massage in the treatment of exercise-induced muscle damage.

The purpose of this investigation was to, firstly, examine the effects of repeated applications of ice massage on the indirect markers associated with muscle damage using a within-subjects cross-over design and secondly, to examine how ice massage affects muscle function in both static and dynamic contractions following unaccustomed eccentric exercise. Twelve males performed damaging exercise on two separate occasions. The protocol consisted of three sets of 10 maximal eccentric repetitions of the elbow flexors using isokinetic dynamometry. Subjects were randomly assigned to an ice massage group or placebo group and received treatments immediately post-exercise, 24 and 48 h post-exercise. Muscle function (maximal isometric, slow and fast isokinetic contractions), creatine kinase, myoglobin, muscle soreness, limb girth and range of motion were measured pre, immediately post, 24, 48, 72 and 96 h post-exercise. Significant time effects were observed for all dependent variables (P<0.05). There were no significant differences between treatments. Ice massage is ineffective in reducing the indirect markers associated with exercise-induced muscle damage and enhancing recovery of muscle function in male exercisers unaccustomed to eccentric biased exercise.

Comparison of the Lactate Pro and Analox GM7 blood lactate analysers.

The purpose of this study was firstly, to determine the level of agreement between the Lactate Pro and Analox GM7 for the measurement of blood lactate, and secondly, to examine whether these analysers may be used interchangeably to identify lactate parameters routinely used in the physiological assessment of athletes. Twenty well-trained male cyclists performed an incremental cycle ergometry test; duplicate blood samples were taken simultaneously throughout the test for lactate determination using the two analysers. Power output and heart rate at LT, LT1, 2 mmol.L-1, and 4 mmol.L-1 were calculated from the lactate values obtained from the two analysers. There was a strong linear relationship between the two analysers (Lactate Pro=1.4541xAnalox GM7-0.1287; R2=0.969, p<0.001; SEE=0.704) though the Lactate Pro overestimated blood lactate when compared to the Analox GM7; 95% ratio limits of agreement (Lactate Pro/Analox GM7) were 1.40x//1.35. Differences were found between analysers for power output and heart rate at LT1 (p<0.01), 2 mmol.L-1 (p<0.001), and 4 mmol.L-1 (p<0.001); no differences were found between analysers for power output or heart rate at LT. In conclusion, the average difference in blood lactate concentration measured by the Lactate Pro and the Analox GM7 was 40%, with 95% of measures differing by between 4% and 89%. This poor level of agreement and the significant differences between the two analysers in power output and heart rate associated with a number of lactate parameters indicate that these analysers should not be used interchangeably.

Ice massage. Effects on exercise-induced muscle damage.

AIM: The purpose of this study was to examine the effects of ice massage on the signs and symptoms associated with exercise-induced muscle damage. METHODS: Nine recreationally resistance trained males performed an exercise protocol designed to induce muscle damage on 2 separate occasions; this was performed on the dominant or non-dominant arm in a random cross over design. The protocol consisted of 3 sets of 10 repetitions of single arm biceps curls, at 70% of a pre-determined one repetition maximum (1RM), with the eccentric phase of the contraction extended to 7 seconds. Subjects were also randomly assigned to an ice massage group or control group in the cross over design and received treatments immediately post-exercise, 24 hours and 48 hours post-exercise. 1RM, plasma creatine kinase (CK), muscle soreness (DOMS), limb girth and range of motion (ROM) were measured pre, immediately post, 24 hours, 48 hours and 72 hours post-exercise. RESULTS: Significant time effects were observed for all dependent variables (p<0.05), though no significant group effects were observed. A group by time interaction was found for CK (p<0.05), which at 72 hours post-exercise was significantly lower in the ice massage group (p<0.05). CONCLUSION: These results indicate that although ice massage reduces the appearance of CK it has no other effect on signs and symptoms associated with exercise-induced muscle damage.

The efficacy of ergometry determined heart rates for flatwater kayak training.

The aim of this study was to investigate the use of incremental ergometry determined heart rate training intensities for the control of kayak ergometer and open water kayak training. Eight well-trained male kayakers completed a maximal incremental exercise test on an air-braked kayak ergometer for the determination of LT(1) (the power output at which blood lactate concentration increased by > or = 1 mmol x L(-1)), the associated heart rate (HR-LT(1)), VO(2)peak, maximal heart rate and maximal aerobic power. Subjects then performed 20 min trials of kayak ergometry (E), open water kayaking in a single kayak (K1) and open water kayaking in a four-seat kayak (K4) at HR-LT(1). During the three trials, heart rate was continuously measured, and blood lactate concentration, rating of perceived exertion (RPE) and stroke rate were determined every 5 min. In all trials, exercise at HR-LT(1) resulted in stable blood lactate concentrations and a stable RPE. Comparison of the three trials demonstrated that the only difference was for RPE, which was lower in (K4) than in (E), (p < 0.05). The results demonstrate that the prescription of HR-LT(1) elicits similar blood lactate concentrations during kayak ergometer and open water kayak training in both single and team boats.

Comparison of physiological responses to open water kayaking and kayak ergometry.

This study compared the physiological responses of simulated kayaking on a K1 ERGO kayak ergometer with open water paddling. Nine well-trained male kayakers (VO2peak 4.27 +/- 0.58 L x min(-1), age 24 +/- 4 yr, mass 77.3 +/- 6.4 kg, height 179.5 +/- 5.3 cm; [mean +/- SD]) performed two 4 min exercise bouts on open water (OW) and on an air braked kayak ergometer (Erg). During exercise, expired air and heart rate (HR) were continuously measured. The distance covered during OW (992 +/- 47.1 m) was highly correlated (r2 = 0.86) with the total work performed in Erg (47.64 +/- 7.67 kJ). There were no differences between trials for oxygen uptake, carbon dioxide production or estimated carbohydrate oxidation. However, during OW, minute ventilation was significantly higher at 60 and 90 s (104.2 +/- 16.4 vs. 92.6 +/- 20.4 L x min(-1) and 120.5 +/- 15.8 vs. 111.7 +/- 17.6 L x min(-1) for 60 and 90 s, respectively, p < 0.05), and HR was higher in OW during the first minute (120 +/- 20 vs. 104 +/- 19 beats x min(-1), 164 +/- 8 vs. 147 +/- 18 beats x min(-1) and 178 +/- 6 vs. 170 +/- 7 beats x min(-1) for 0, 30, and 60 s, respectively, p < 0.05). There were no differences in peak VO2 between OW and Erg (4.10 +/- 0.49 vs. 4.09 +/- 0.53 L x min(-1), respectively) nor in post-exercise blood (lactate) (6.43 +/- 1.47 vs. 6.59 +/- 0.99 mmol x L(-1), respectively). We conclude that the K1 ERGO accurately simulates the physiological demands of short-term, high-intensity kayaking.