OBJECTIVE: This study investigated the effectiveness of the UDP in the last 6 wk of rehabilitation.
DESIGN: Pre-post study with 2-tailed paired t tests for limited a priori comparisons to examine differences.
SETTING: National Sports Institute of Malaysia.
PARTICIPANTS: 24 Malaysian national athletes.
INTERVENTIONS: 7 sessions/wk of 90 min with 3 sessions allocated for 5 or 6 UDP exercises.
MAIN OUTCOMES: Significant improvements for men and women were noted. Tests included 20-m sprint, 1-repetition-maximum single-leg press, standing long jump, single-leg sway, and a psychological questionnaire.
RESULTS: For men and women, respectively, average strength improvements of 22% (d = 0.96) and 29% (d = 1.05), sprint time of 3% (d = 1.06) and 4% (d = 0.58), and distance jumped of 4% (d = 0.59) and 6% (d = 0.47) were noted. In addition, athletes reported improved perceived confidence in their abilities. All athletes improved in each functional test except for long jump in 2 of the athletes. Mediolateral sway decreased in 18 of the 22 athletes for the injured limb.
CONCLUSION: The prevention training with UDP resulted in improved conditioning and seems to decrease mediolateral sway.
METHODS: Eleven trained male distance runners performed 7 randomized runs at different velocities (8, 10, 12, 14, 16, 18, and 20 km·h-1), each lasting 45 seconds on an instrumented treadmill in normoxia (fraction of inspired oxygen [FiO2] = 20.9%), moderate hypoxia (FiO2 = 16.1%), high hypoxia (FiO2 = 14.1%), and severe hypoxia (FiO2 = 13.0%). Continuous assessment of Tissue Saturation Index (TSI) in the vastus lateralis muscle was conducted using near-infrared spectroscopy. Subsequently, changes in TSI (ΔTSI) data over the final 20 seconds of each run were compared between velocities and conditions.
RESULTS: There was a significant velocity × condition interaction for ΔTSI% (P < .001, ηp2=.19), with a smaller ΔTSI% decline in normoxia compared with high hypoxia and severe hypoxia at 8 km·h-1 (g = 1.30 and 1.91, respectively), 10 km·h-1 (g = 0.75 and 1.43, respectively), and 12 km·h-1 (g = 1.47 and 1.95, respectively) (pooled values for all conditions: P < .037). The ΔTSI% decline increased with each subsequent velocity increment from 8 km·h-1 (-9.2% [3.7%]) to 20 km·h-1 (-22.5% [4.1%]) irrespective of hypoxia severity (pooled values for all conditions: P < .048).
CONCLUSIONS: Running at slower velocities in conjunction with high and severe hypoxia reduces vastus lateralis muscle oxygenation levels. Muscle ΔTSI% proves to be a sensitive indicator, underscoring the potential use of near-infrared spectroscopy as a reference index of internal load during treadmill runs.
OBJECTIVE: To assess the impact of a three-week UDP program onstrength, power, and proprioceptive measures.
DESIGN: Matched-group, pre- post design.
SETTING: National Sports Institute.
PARTICIPANTS: Twenty-one international-level female field hockey athletes.
INTERVENTIONS: Two 45 min UDP sessions were incorporated into each week of a three week training program (total 6 sessions).
MAIN OUTCOME MEASURES: One-repetition maximum strength, lower limb power, 20 m running speed, and proprioception tests were performed before and after the experimental period.
RESULTS: Substantial improvements in running sprint speed at 5- (4.4 ± 2.6%; Effect Size [ES]: 0.88), 10- (2.1 ± 1.9%; ES: 0.51), and 20-m (1.0 ± 1.6%; ES: 0.23) were observed in the UDP group. Squat jump performance was also clearly enhanced when compared to the control group (3.1 ± 6.1%; ES: 0.23). Small but clear improvements in maximal strength were observed in both groups.
CONCLUSION: A three week UDP can elicit clear enhancements in running sprint speed and concentric-only jump performance. These improvements are suggestive of enhanced explosive strength and are particularly notable given the elite training status of the cohort and relatively short duration of the intervention. Thus, we would reiterate the statement by Gruber and colleagues (2004) that sensorimotor training is a "highly efficient" modality for improving explosive strength.