Arterial blood pressure and forearm vascular conductance responses to sustained and rhythmic isometric exercise and arterial occlusion in trained rock climbers and untrained sedentary subjects

Abstract

Cardiovascular responses to sustained and rhythmic (5 s on, 2 s off) forearm isometric exercise to fatigue at 40% maximal voluntary contraction (MVC) and to a period of arterial occlusion were investigated in elite rock climbers (CLIMB) as a trained population compared to non-climbing sedentary subjects (SED). Blood pressure (BP), monitored continuously by Finapres, and forearm blood flow, by venous occlusion plethysmography, were measured and used to calculate vascular conductance. During sustained exercise, times to fatigue were not different between CLIMB and SED. However, peak increases in systolic (S) BP were significantly lower in CLIMB [25 (13) mmHg; (3.3 (1.7) kPa] than in SED [48 (17) mmHg; (6.4 (2.3) kPa] (P < 0.05), with a similar trend for increases in diastolic (D) BP. Immediately after sustained exercise, forearm conductance was higher in CLIMB than SED (P < 0.05) for up to 2 min. During rhythmic exercise, times to fatigue were two fold longer in CLIMB than SED [853 (76) vs 420 (69) s, P < 0.05]. Increases in SBP were not different between groups except during the last quarter of exercise when they fell in CLIMB. Conductance both during and after rhythmic exercise was higher in CLIMB than in SED. Following a 10-min arterial occlusion, peak vascular conductance was significantly greater in CLIMB than SED [0.597 (0.084) vs 0.431 (0.035) ml x min(-1) x 100 ml(-1) x mmHg(-1); P < 0.05]. The attenuated BP response to sustained isometric exercise could be due in part to enhanced forearm vasodilatory capacity, which also supports greater endurance during rhythmic exercise by permitting greater functional hyperaemia in between contraction phases. Such adaptations would all facilitate the ability of rock climbers to perform their task of making repetitive sustained contractions.

Estimation of hand and wrist muscle capacities in rock climbers

“…Further investigations are needed to determine if this conclusion is also valid for the wrist adduction-abduction and the forearm pronation-supination muscle groups. In a similar way, the capacities of climbers' intrinsic hand muscles were not significantly higher which is in accordance with the studies which demonstrated that climbers do not achieve higher performances for non-specific climbing tasks such as hand dynamometer tests (Ferguson and Brown 1997). To sum up, this study demonstrates that current climbing practice and training methods do not result in homogeneous improvements of muscle capacities, since only finger flexors are enhanced without modifications of other hand and wrist muscles.…”

“…Diff EMG represents the mean (among all tasks and all subjects of a population) of the differences between the estimated mechanical activity of each muscle group and the recorded EMG activity. Ferguson and Brown 1997;Grant et al 2003;Quaine et al 2003) or iso-kinetic exercises (Schweizer and Furrer 2007). These studies reported the results of external torques and forces measured during the tests and brought interesting knowledge.…”

“…Climbers are also able to maintain high levels of fingertip forces over longer periods than non-trained individuals; mainly thanks to an increase in their forearm muscles' vascularisation Philippe et al 2012). In contrast to these capabilities, several studies observed that climbers do not necessarily present higher performances during non-climbing tasks such as handgrip exercises where the forces are applied on the entire surface of the finger pad, and during full power-grip tasks (Cutts and Bollen 1985;Ferguson and Brown 1997).…”

Forearm muscle oxidative capacity index predicts sport rock-climbing performance

“…Given the relatively small amount of activated skeletal muscle in the forearms, the lack of relationship between conduit artery (brachial) blood flow and performance is not surprising and supports previous -albeit more indirect -findings. The earlier studies reported that forearm vascular conductance is higher in trained rock climbers compared to a control group after both sustained and intermittent handgrip exercise, as well as post 10 min arterial occlusion (Ferguson and Brown 1997). …”

Fatores determinantes do desempenho na escalada esportiva: umas das contribuições da professora Maria Augusta Kiss para o desenvolvimento das ciências do esporte no Brasil

“…For instance, in the study by Watts et al (6) previously mentioned, the authors did not verify significant differences of MHS between the semifinalists and finalists of a qualifying of the Sport Climbing World Cup. In another subsequent study, Fergunson and Brown (7) observed that the MHS of a group of elite climbers did not differ either from a sedentary group. However, in this investigation the TBM of the subjects was not measured, which made the assessment of the MHS in relation to the TBM impossible.…”