Wing-Kai Lam

Effect of shoe heel modifications on shock attenuation and joint loading during extreme lunge movement in elite badminton players

In badminton, lunging is essential and frequently, it accounts for approximately 15% of all badminton movements in competitive single game (Kuntze et al. 2010). Players exhibited about 2.5 BW ground reaction force during each lunge (Kuntze et al. 2010) and this would result in a high force load and painful symptoms on the patellar tendon (Fahlstrom et al. 2002, Peers and Lysens 2005, Boesen et al. 2006). In competitive badminton games, players often performed the extreme lunges having more than 40 degrees of the initial shoe-ground angle that may result in greater impact forces and joint loading than normal lunging. Because the location of initial contact between shoe and ground is around heel edge of shoe, particular modification on the heel shape would be plausible to reduce ground reaction forces and knee joint loading. Currently, no scientific guideline is available to show how the heel modifications of badminton shoe influences heel cushioning during lunge.

Does shoe heel design influence ground reaction forces and knee moments during maximum lunges in elite and intermediate badminton players

Background Lunge is one frequently executed movement in badminton and involves a unique sagittal footstrike angle of more than 40 degrees at initial ground contact compared with other manoeuvres. This study examined if the shoe heel curvature design of a badminton shoe would influence shoe-ground kinematics, ground reaction forces, and knee moments during lunge. Methods Eleven elite and fifteen intermediate players performed five left-forward maximum lunge trials with Rounded Heel Shoe (RHS), Flattened Heel Shoe (FHS), and Standard Heel Shoes (SHS). Shoe-ground kinematics, ground reaction forces, and knee moments were measured by using synchronized force platform and motion analysis system. A 2 (Group) x 3 (Shoe) ANOVA with repeated measures was performed to determine the effects of different shoes and different playing levels, as well as the interaction of two factors on all variables. Results Shoe effect indicated that players demonstrated lower maximum vertical loading rate in RHS than the other two shoes (P < 0.05). Group effect revealed that elite players exhibited larger footstrike angle, faster approaching speed, lower peak horizontal force and horizontal loading rates but higher vertical loading rates and larger peak knee flexion and extension moments (P < 0.05). Analysis of Interactions of Group x Shoe for maximum and mean vertical loading rates (P < 0.05) indicated that elite players exhibited lower left maximum and mean vertical loading rates in RHS compared to FHS (P < 0.01), while the intermediate group did not show any Shoe effect on vertical loading rates. Conclusions These findings indicate that shoe heel curvature would play some role in altering ground reaction force impact during badminton lunge. The differences in impact loads and knee moments between elite and intermediate players may be useful in optimizing footwear design and training strategy to minimize the potential risks for impact related injuries in badminton.

Effect of forefoot bending stiffness of badminton shoe sole on lower leg kinematics during match-like situations

While the subject number is low, barefoot running does not appear to strengthen foot structures. In fact, the FHB tendon was stiffer in traditionally shod runners. This difference may be related to loading as there appears to be a relationship between tendon stiffness and average running mileage in traditionally shod runners (see Figure 2). Even with a larger mileage range (20–80 miles/week), FHB tendon material stiffness for barefoot runners seems to have no relationship with average running mileage. The results of the current study do not support the idea that running in minimalistic footwear strengths foot structures. More subjects will be recruited to increase statistical power. Ideally, an experimental, longitudinal study will also be performed to test for causation.

Round reaction forces and knee joint moments during basketball jab step cutting maneuver

Basketball game involves multi-directional cutting maneuvers (CMs) in response to the opponents. Lab based cutting maneuver tests involving lateral shuffling and 45 cutting, have reported high ground reaction forces (GRFs) (2.97 BW, Dayakidis and Boudolos, 2006) and external knee moments (2Nm/kg, Beiser et al. 2001) which was considered as risk factor for anterior cruciate ligament (ACL) injuries (Boden et al. 2000). A frequently used jab step CMs in a basketball game is the fake, plant and cut movements. This is particularly used by offensive players with or without the ball in hand during a tight one-on-one situation. The offensive player usually gives a quick fake to the dominant side, which involves leg planting and shoulder movement followed by speed cutting to the opposite direction of which the defender is directed. There is a lack of biomechanics information in the current literature about this highly relevant CM. There is unknown about the magnitudes of GRFs and knee moments during this jab step CM and the potential influences from different basketball footwears.

The relationship between shoe torsion and athletic performance during badminton maneuvers

Torsion is defined as the relative movement between the forefoot and rearfoot along the longitudinal axis of the foot. It has been suggested that increased torsional movement between forefoot and rearfoot may reduce pronation of the foot and thus, reduce the risk of injuries during running (Stacoff et al. 1991). However, whether a large torsional movement would be beneficial for other sport activities is unknown. Badminton is characterized as a sport that requires highly intense activity with short rest pauses (Fahlstrom et al. 2002). During badminton, the foot experiences dynamic movement as it requires diverse foot-steps on the court (Wang et al. 2009). Currently, no study has investigated how torsional characteristics of the shoe influence athletic performance.

Do running speed and shoe cushioning influence impact loading and tibial shock in basketball players

Background Tibial stress fracture (TSF) is a common injury in basketball players. This condition has been associated with high tibial shock and impact loading, which can be affected by running speed, footwear condition, and footstrike pattern. However, these relationships were established in runners but not in basketball players, with very little research done on impact loading and speed. Hence, this study compared tibial shock, impact loading, and foot strike pattern in basketball players running at different speeds with different shoe cushioning properties/performances. Methods Eighteen male collegiate basketball players performed straight running trials with different shoe cushioning (regular-, better-, and best-cushioning) and running speed conditions (3.0 m/s vs. 6.0 m/s) on a flat instrumented runway. Tri-axial accelerometer, force plate and motion capture system were used to determine tibial accelerations, vertical ground reaction forces and footstrike patterns in each condition, respectively. Comfort perception was indicated on a 150 mm Visual Analogue Scale. A 2 (speed) × 3 (footwear) repeated measures ANOVA was used to examine the main effects of shoe cushioning and running speeds. Results Greater tibial shock (P < 0.001; η2 = 0.80) and impact loading (P < 0.001; η2 = 0.73–0.87) were experienced at faster running speeds. Interestingly, shoes with regular-cushioning or best-cushioning resulted in greater tibial shock (P = 0.03; η2 = 0.39) and impact loading (P = 0.03; η2 = 0.38–0.68) than shoes with better-cushioning. Basketball players continued using a rearfoot strike during running, regardless of running speed and footwear cushioning conditions (P > 0.14; η2 = 0.13). Discussion There may be an optimal band of shoe cushioning for better protection against TSF. These findings may provide insights to formulate rehabilitation protocols for basketball players who are recovering from TSF.

Effects of forefoot bending stiffness of badminton shoes on agility, comfort perception and lower leg kinematics during typical badminton movements

Abstract This study investigated whether an increase in the forefoot bending stiffness of a badminton shoe would positively affect agility, comfort and biomechanical variables during badminton-specific movements. Three shoe conditions with identical shoe upper and sole designs with different bending stiffness (Flexible, Regular and Stiff) were used. Elite male badminton players completed an agility test on a standard badminton court involving consecutive lunges in six directions, a comfort test performed by a pair of participants conducting a game-like practice trial and a biomechanics test involving a random assignment of consecutive right forward lunges. No significant differences were found in agility time and biomechanical variables among the three shoes. The players wearing the shoe with a flexible forefoot outsole demonstrated a decreased perception of comfort in the forefoot cushion compared to regular and stiffer conditions during the comfort test (p < 0.05). The results suggested that the modification of forefoot bending stiffness would influence individual perception of comfort but would not influence performance and lower extremity kinematics during the tested badminton-specific tasks. It was concluded that an optimisation of forefoot structure and materials in badminton shoes should consider the individual’s perception to maximise footwear comfort in performance.

Differences in impact characteristics, joint kinetics and measurement reliability between forehand and backhand forward badminton lunges

ABSTRACT This study identified the effect of badminton lunging directions on impact characteristics, joint kinetics and measurement reliability. A total of 14 badminton players performed 20 lunges in both forehand and backhand sides. Ground reaction force (GRF) and three-dimensional joint moment variables were determined for further analyses. Paired t-tests and Wilcoxon signed-rank tests were performed to determine any differences between the two lunge directions and intra-class correlation (ICC) and sequential averaging analysis (SAA) were used to estimate the minimum number of trials. Compared to the forehand side, participants experienced significantly larger total GRF impulse (+ 3.8%, p = 0.021) and transverse moment (hip + 63.5%, p < 0.001; knee + 80.7%, p = 0.011), but smaller hip (−7.7%), knee (−18.7%) and ankle frontal moments (−58.0%, p < 0.05) in backhand lunges. The minimum number of trials was similar for both lunge directions, as the averaged absolute differences was less than one in both ICC and SAA. Furthermore, smaller minimal number of trials was determined by the ICC (7.9–8.0), compared with the SAA approach (9.5–10.3). Lunge direction would influence GRF and joint loading, but not on the measurement reliability. These results give important insights to establish performance or equipment evaluation protocols during badminton lunges.

Effects of Shoe Top Visual Patterns on Shoe Wearers’ Width Perception and Dynamic Stability

Visual illusions caused by varied orientations of visual patterns may influence the perception of space and size, possibly affecting body stability during locomotion. This study examined the effect of variations in shoe top visual patterns on perception and biomechanical stability while walking and running. Twenty healthy adults performed five walking and running trials along an instrumented walkway when wearing shoes with five different striped patterns (plain, vertical, outward, horizontal, and inward). Before these locomotion trials, participants ranked their perceptions of shoe width. We used synchronized force platform and motion capturing systems to measure ground reaction force, mediolateral center of position displacement, ankle inversion and eversion, ankle excursion, and maximum eversion velocity. We rated stability perception on a 150-mm visual analog scale immediately after each shoe condition. Data analyses indicated that participants perceived plain and horizontal striped shoes as significantly wider than inward and vertical patterned shoes. During walking, participants wearing shoes with plain and horizontal striped patterns demonstrated smaller mediolateral center of position displacement, maximum eversion velocity, and ankle range of motion when compared with walking when wearing outward and vertical striped patterns; when running, we observed a similar effect for maximum eversion velocity. Thus, certain visual patterns on the tops of shoes influence the wearers’ width perception and locomotion in ways that affect ankle stability during walking and running, with implications for risk of injury.

Kinetics and perception of basketball landing in various heights and footwear cushioning

Background The previous studies on basketball landing have not shown a systematic agreement between landing impacts and midsole densities. One plausible reason is that the midsole densities alone used to represent the cushioning capability of a shoe seems over simplified. The aim of this study is to examine the effects of different landing heights and shoes of different cushioning performance on tibial shock, impact loading and knee kinematics of basketball players. Methods Nineteen university team basketball players performed drop landings from different height conditions (0.45m vs. 0.61m) as well as with different shoe cushioning properties (regular, better vs. best-cushioned). For each condition, tibial acceleration, vertical ground reaction force and knee kinematics were measured with a tri-axial accelerometer, force plate and motion capture system, respectively. Heel comfort perception was indicated on the 150-mm Visual Analogue Scale. A 2 (height) x 3 (footwear) ANOVA with repeated measures was performed to determine the effects of different landing heights and shoe cushioning on the measured parameters. Results We did not find significant interactions between landing height and shoe conditions on tibial shock, impact peak, mean loading rate, maximum knee flexion angle and total ankle range of motion. However, greater tibial shock, impact peak, mean loading rates and total ankle range of motion were determined at a higher landing height (P < 0.01). Regular-cushioned shoes demonstrated significantly greater tibial shock and mean loading rate compared with better- and best-cushioned shoes (P < 0.05). The correlation analysis indicated that the heel comfort perception was fairly associated with impact peak and mean loading rate regardless of heights (P < 0.05), but not associated with tibial shock. Conclusions Determination of shoe cushioning performance, regardless of shoe midsole materials and constructions, would be capable in order to identify optimal shoe models for better protection against tibial stress fracture. Subjective comfort rating could estimate the level of impact loading in non-laboratory based situations.