International SportMed Journal - Volume 12, Issue 1, 2011
Volume 12, Issue 1, 2011
Changes in biochemical parameters after a 20-hour ultra-endurance kayak and cycling event : original research articleSource: International SportMed Journal 12, pp 1 –6 (2011)More Less
Background: Numerous studies have analyzed changes in biochemical blood parameters in ultra-endurance events but never in a kayak and cycling ultra-endurance event. Research question: The objective of this study was to analyze blood biochemistry changes in creatine kinase, urea, triglycerides, haemoglobin, creatinine, creatinine clearance and lactate in a 20-hour ultra-endurance kayak and cycling event. Type of study: Descriptive field study. Methods: The parameters of creatine kinase, urea, triglycerides, haemoglobin, creatinine, creatinine clearance and lactate were measured in 16 subjects (mean ±SD age 28.0±3.4 years; height 176.0±5.5cm; body mass 71.8±9.2kg) who participated in an ultra-endurance event before, and at the end of the race, in which they covered 100km in a kayak and 65km on a mountain bike. Results: Significant changes were observed (p<0.05) between the pre- and post race samples in the variables: creatine kinase and urea, but not between those of haemoglobin, creatinine, creatinine clearance, triglycerides and lactate. Conclusions: A 20-hour kayak and cycling race caused an increase in protein catabolism and muscle breakdown, but did not affect the subjects' renal function.
Lower limb muscle activation during a 40km cycling time trial : co-activation and pedalling technique : original research articleSource: International SportMed Journal 12, pp 7 –16 (2011)More Less
Background: Knee extensors muscle activation could be optimized by a reduced activation of knee joint flexor muscles (co-activation) during fatigue. Time trial events are based on the management of energy resources by controlling muscle activation by focusing on optimizing performance and avoiding premature fatigue. Research question: Is there a reduction on muscle co-activation and variability of muscle activity during the recovery phase of pedal cycle which could influence pedalling technique and time trial performance? Type of study: Cross-sectional. Methods:Subjects: Eight triathletes. Experimental procedure: Maximal oxygen uptake and power output evaluation session. Cycling time trial performance session with the measurement of muscle activity by means of electromyography. Outcome measurements: Knee and ankle muscle co-activation, muscle activation variability, and muscle activation during the recovery phase of a pedal cycle. Results: Increased variability of biceps femoris and increased recruitment of vastus lateralis at the end of the time trial. No differences found for muscle co-activation. Conclusion: Individual strategies regarding biceps femoris activation are suggested based on changes in muscle activation variability. Vastus lateralis showed increased activation during the recovery phase, probably as an attempt to improve power output in the propulsion phase.
Training in a shallow pool : its effect on upper extremity strength and total body weight in postmenopausal women : original research articleSource: International SportMed Journal 12, pp 17 –29 (2011)More Less
Background: The decrease in muscle mass and muscular strength and the increase in total body weight have significant implications for the health and functioning of postmenopausal women. Exercising in water has become increasingly popular as a means of delaying the physiological decline associated with age in middle-aged and older women. Research question: Is a 12-month aerobic and resistance water training program in a shallow pool effective in increasing muscle strength and decreasing total body weight in postmenopausal women? Type of study: Randomised controlled study. Methods: Thirty-eight subjects were randomly assigned to an exercise group (EG; n = 21) and a control group (CG; n = 17). The exercise group enrolled in a systematic aerobic and resistance training programme for 12 months performed at a frequency of 2 sessions per week, 45 minutes per session. Upper-extremity biokinetic strength and body mass index (BMI) were measured before and after the intervention. CG participants were physically active. Results: EG participants improved significantly (p ≤ 0.05) in mean force (MF: 7.92%), mean power (MP: 9.08%) and mean work (MW: 9.3%). Mean stroke length decreased significantly (p ≤ 0.05) in EG (-5.68%) and in CG (-11.5%). BMI was also significantly decreased (p ≤ 0.05) in EG participants (-2.75%). Conclusions: These results indicate that training in a shallow pool has significant implications for improving upper extremity muscular strength and total body weight in postmenopausal women.
The effect of a low impact exercise training programme on the well-being of Greek postpartum women : a randomised controlled trial : original research articleSource: International SportMed Journal 12, pp 30 –38 (2011)More Less
Background: Existing evidence on guidance of postpartum fitness activities is scarce. Research question: To examine the effects of a low impact exercise programme on the physical and psychosocial well-being of postpartum women. Type of study: Randomised controlled trial. Methods: Forty healthy primiparous Greek women were randomly assigned at 4-6 week postpartum to follow either a low impact exercise training programme, involving 50-60 min of aerobic, stretching and strengthening exercise, 3 days a week, for 12 weeks (experimental group; n=20) or no training programme at all (control group; n=20). Prior to initiation of the study and 12 weeks later, participants answered the Lederman Postpartum Self-Evaluation Questionnaire, in order to evaluate psychosocial well-being, and mothers' body weight and infant feeding methods were recorded, in order to evaluate women's physical well-being. All data were analyzed using Mancova test, a Linear Mixed model and the Chi-square test. Results: Psychosocial well-being parameters were significantly improved in the experimental group, as compared with the control group, including "quality of partner relationship" (p<.05) and "satisfaction from labour and delivery experience" (p<.05). Differences in body weight changes between the two groups were insignificant, while the experimental group was more stable regarding the infant feeding method after the 12-week period (p = ns) as opposed to the control group (p<0.001). Conclusions: Implementation of a low impact exercise training programme appears to improve the psychosocial well-being of postpartum women. Healthcare providers should consider incorporation of a low impact exercise training programme into their management plan of women after childbirth.
Relationships between head-out aquatic exercise kinematics and musical cadence : analysis of the side kick : original research articleSource: International SportMed Journal 12, pp 39 –52 (2011)More Less
Background: Head-out aquatic exercises became one of the most popular physical activities within the health primarily and thirdly prevention system. Music is seen as one of the most important aspects when conducting head-out aquatic exercise sessions. Research question: Is there any relationship between musical cadence and the kinematic behaviour when performing aerobic head-out aquatic exercises? It was hypothesized that an increase in music cadence will would impose a decrease of the segment range of motion. Type of study: Experimental, prospective. Methods: Six young and clinically healthy women with at least one year of experience conducting head-out aquatic classes were videotaped in the frontal plane, with a pair of cameras providing a double projection (above and below the water surface). Subjects performed an incremental protocol of five bouts (120b.min-1, 135b.min-1, 150b.min-1, 165b.min-1 and 180b.min-1) with 16 full cycles of the "side kick" exercise. Data processing and calculation of segmental (i.e. hands and feet) and anatomical landmark (i.e. centre of mass) were performed using the software Ariel Performance Analysis System and applying the DLT algorithm. Results: There was a decrease in the cycle period during the incremental protocol. The relationships between the segmental lateral and vertical displacements with the musical cadence were not significant. The segmental velocities on the lateral and vertical components showed significant increases throughout the incremental protocol. Conclusions: The data suggest that segmental velocity increases with increasing cadence, reducing the cycle period and maintaining the segmental displacements.