This study examined the effect of wearing different grades of graduated compression stockings (GCS) on physiological and perceptual measures during and following treadmill running in competitive runners. Nine males and one female performed three 40-min treadmill runs (80 +/- 5% maximal oxygen uptake) wearing either control (0 mmHg; CON), low (12-15 mmHg; LO-GCS), or high (23-32 mmHg; HI-GCS) grade GCS in a double-blind counterbalanced order. Oxygen uptake, heart rate and blood lactate were measured. Perceptual scales were used pre- and post-run to assess comfort, tightness and any pain associated with wearing GCS. Changes in muscle function, soreness and damage were determined pre-run, immediately after running and 24 and 48 h post-run by measuring creatine kinase and myoglobin, counter-movement jump height, perceived soreness diagrams, and pressure sensitivity. There were no significant differences between trials for oxygen uptake, heart rate or blood lactate during exercise. HI-GCS was perceived as tighter (P < 0.05) and more pain-inducing (P < 0.05) than the other interventions; CON and LO-GCS were rated more comfortable than HI-GCS (P < 0.05). Creatine kinase (P < 0.05), myoglobin (P < 0.05) and jump height (P < 0.05) were higher and pressure sensitivity was more pronounced (P < 0.05) immediately after running but not after 24 and 48 h. Only four participants reported muscle soreness during recovery from running and there were no differences in muscle function between trials. In conclusion, healthy runners wearing GCS did not experience any physiological benefits during or following treadmill running. However, athletes felt more comfortable wearing low-grade GCS whilst running.

The aim of this study was to examine the effects of wearing different grades of graduated compression stockings (GCS) on 10-km running performance. After an initial familiarization run, 9 male and 3 female competitive runners (VO₂max 68.7 ± 5.8 ml·kg⁻¹·min⁻¹) completed 4 10-km time trials on an outdoor 400-m track wearing either control (0 mm Hg; Con), low (12-15 mm Hg; Low), medium (18-21 mm Hg; Med), or high (23-32 mm Hg; Hi) GCS in a randomized counterbalanced order. Leg power was assessed pre and postrun via countermovement jump using a jump mat. Blood-lactate concentration was assessed pre and postrun, whereas heart rate was monitored continuously during exercise. Perceptual scales were used to assess the comfort, tightness, and any pain associated with wearing GCS. There were no significant differences in performance time between trials (p = 0.99). The change in pre to postexercise jump performance was lower in Low and Med than in Con (p < 0.05). Mean heart rate (p = 0.99) and blood lactate (p = 1.00) were not different between trials. Participants rated Con and Low as more comfortable than Med and Hi (p < 0.01), Med and Hi were rated as tighter than Low (p < 0.01), all GCS were rated as tighter than Con (p < 0.01), and Hi was associated with the most pain (p < 0.01). In conclusion, GCS worn by competitive runners during 10-km time trials did not affect performance time; however Low and Med GCS resulted in greater maintenance of leg power after endurance exercise. Athletes rated low-grade GCS as most comfortable garments to wear during exercise.

No abstract

Objective: Investigate differences between athletes that responded (improved performance) compared to those that did not, after a 20-day "live high-train low" (LHTL) altitude training camp. Methods:Ten elite triathletes completed 20 days of live high (1545-1650 m), train low (300 m) training. The athletes underwent (i), two 800-m swimming time trials at sea-level (1 week prior to and 1 week after the altitude camp) and (ii) two 10-min standardised submaximal cycling tests at altitude on day 1 and day 20 of the altitude camp. Acute mountain sickness (AMS) was also measured during the camp. Based on their 800-m swimming time trial performances, athletes were divided into responders (improved by 3.2 ± 2.2%, mean ± SD, n=6) and non-responders (decreased by 1.8 ± 1.2%, n=4).Results: Compared to non-responders, the responders had lower exercise heart rates (-6.3 ± 7.8%, mean ± 90% CL, and higher oxygen saturations (1.2 ± 1.3%) at the end of the 10-min submaximal test after the camp. Compared to the responders, the non-responders had substantially higher VE and VE/VO 2 during the submaximal test on day 1 of the altitude training camp, and a substantially higher RER during the submaximal test on day 20 of the camp. As a result of the altitude training, exercise economy of the non-responders compared to the responders deteriorated (i.e., non-responders required more oxygen per watt). Non-responders were 3.0 times (90% CL=0.5-16.6) more likely to suffer symptoms of acute mountain sickness during first 5 days of altitude compared to responders. Conclusion:Changes in SpO 2 , heart rate and some respiratory variables during exercise and resting AMS scores may help determine athletes that respond to LHTL altitude training camps from athletes that fail to respond to such training.

No abstract