Just Fly Performance Podcast

Today’s show is with Boo Schexnayder.  Boo is a current strength coach and former jumps coach at Louisiana State University, and is regarded internationally as a leading authority in training design.  Boo has been a two-time previous guest on the podcast talking about speed and power training setups.  In a world of complexity, and nearly infinite ways to train athletes, Boo knows the art of managing athletic performance by using training means that are not more complex than they need to be. In my coaching (and athletic) years, I have loved looking into all of the complexities, and details of the human body, training, motor learning and biomechanics.  It’s always been a swinging pendulum in terms of digging in to understand important training nuances, but then zooming back out, to pull along the key pieces of what it really important, both in general, and for each individual athlete. When we over-complicate training, over-coach, and give out exercises that require too much distraction from actual outputs or muscular adaptations, we create a diminished experience for the athlete, and also create a program that is harder to learn from as a coach.  Knowing how and when to make the complex simple is a mark of an accomplished coach who can really transmit training to an athlete in a way that allows them to self-organize to their highest potential, both on the level of skill development, and maximal outputs. On the show today, Boo goes in detail on his own upbringing and mentorships in coaching that have led him to become the coach he is today.  He speaks particularly how his work in the rehab process gave him increased confidence in his regular coaching abilities.  Boo will speak on the process of how far he will go on the complexity rung in the gym, and how he balances coaching skill and technique with the self-organizing ability of the athlete.  Finally, Boo gives some of his thoughts on training that focuses on an athlete’s strength, and his take on heavy partial lifts in the gym in respect to the total training system. Today’s episode is brought to you by SimpliFaster and Lost Empire Herbs. For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 5:02 – Boo’s early development as a coach, early mentors, and his work in rehab that led him to where he is now 15:30 – Some specifics that Boo learned from the world of rehabilitation that intertwined with his performance coaching practice, and how rehab and training follow the same principles and draw from the same well 21:50 – Boo’s advice on arriving at the place where things can be made optimally simple in coaching 25:10 – Why coaches end up chasing things in athletics that aren’t that important 36:28 – Where Boo draws the line on complexity in the weightroom to the point where exercises aren’t helping to accomplish the primary goal of training 40:26 – The extent of complexity Boo would utilize for single leg movements 46:01 – How athletes must train their strengths in order to potentiate their weaknesses 52:48 – A discussion on how the Buffalo Bills didn’t squat in season and still experienced substantial success 57:20 – Boo’s take on heavy quarter squats and partial step ups in performance training (vs. full range of motion) “The earliest (change) is when I finally understood specificity and I developed a healthy non-respect for coaching culture, I realized that a lot of coaching is traditional and needs to be evaluated” “Another bright light that came on is when I got involved in the rehab field” “I think the key thing to keeping things simple is understanding what you are trying to accomplish” “So much of what we do in traditional coaching cultures is just filler work” “I feel that one thing that holds back lots of coaches is technology, there is so much technology out there that so many coaches have b...

Nick Winkelman is the head of athletic performance & science for the Irish Rugby Football Union and a renowned expert in coaching science. He discusses the importance of blending psychological understanding with physical training to create meaningful learning experiences for athletes. The conversation highlights how effective communication and soft skills can enhance athlete engagement. Winkelman also emphasizes the power of storytelling in coaching and the beneficial role of external cues in improving performance.

Today’s show is with Rob Gray, professor at Arizona State University and Host of the Perception & Action Podcast.  Rob Gray is a professor at Arizona State University who has been conducting research on and teaching courses related to perceptual-motor skill for over 25 years.  Rob focuses heavily on the application of basic theory to address real-world challenges, having consulted with numerous professional and governmental entities, and has developed a VR baseball training system that has been used in over 25 published studies.  Rob is the author of the book “How We Learn to Move: A Revolution in the Way We Coach and Practice Sports Skills”. When it comes to anything we do athletically: playing a sport, sprinting, lifting weights, even holding an isometric position; all of these things are learned skills.  So often, the various compartments of athletics, the sport coach, the strength coach, the rehab specialist, are relatively disconnected, and there is often no common playbook when it comes to athletics and the learning process. The principles of the way we learn, and how this learning fits with our movement strategy and ability, are universal.  By understanding what it takes to be a better mover via the learning process, we have an understanding of the general process of athletic performance training from a broader frame of mind. On today’s show, Rob Gray speaks about the fallacy of training a “perfect technique” via drills or repeated cues.  He talks about why using a constraints-led approach to help shore up any key movement attractors (technique) is an ideal way to facilitate skill development.  Rob will get into his take on how to approach learning the “fundamentals” in any sport skill, and also get into important concepts of variability in sport, the differences between novice and elite in variability, and then how there can be “good” or “bad” variability in sport training.  Finally, Rob covers the role of variability in injury prevention, and talks about the sport coach/strength coach relationship in light of variability and the constraints led approach to skills. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 5:05 – The story of Tim Tebow, and how he was so dominant on the NCAA level, but why his NFL career was very unsuccessful from a perspective of throwing biomechanics 9:08 – Rob’s take on the idea of “perfect technique” 13:47 – Approaching the “fundamentals” in any given skill, in the learning process 23:37 – Looking at drill-work in sport and its original intended purpose 25:33 – How much variability elite versus amateur athletes exhibit in their skills 28:59 – Variability across a spectrum of skills, such as running in football versus running on a track in sprinting 32:42 – Using variability in “basic” sports such as track and field or swimming 39:17 – How variability changes as one moves from novice, to intermediate, to expert, particularly on the level of an individual sport, like track and field 45:28 – Rob’s take on variability and injury-prevention 50:57 – The idea of donor sports and how those sports can offer helpful variability to one’s eventual sport specialization 56:35 – How strength coaches might be able to use variability in the gym that might connect to skills athletes are trying to improve on the field “There can’t be one perfect, ideal way, because the world is not staying the same around you” “Being skillful is not about repeating the same solution to the problem, it’s about repeating coming up with solutions to problems” “I like to think about giving athletes problems to solve instead of the solution”

Today’s show is with performance director Daniel Bove.  After spending several seasons with the Atlanta Hawks and Phoenix Suns, Daniel is now the Director of Performance and Sports Science for the New Orleans Pelicans, and is also the author of the book, “The Quadrant System, Navigating Stress in Team Sport”. As Michael Zweifel has said previously on the podcast, every coach should have the opportunity to work with youth athletes, and pro sports, at some point in their career.  I’ve done a lot of shows talking about youth sport concepts, as well as principles of training through the lens of a child development, but I haven’t done as many shows detailing some of the nuances of working with a pro population specifically. When it comes to that other end of the spectrum, with professional athletes, the art of strength & conditioning is largely the art of “load management” and stress consolidation, especially over the course of long competitive seasons.  This art of training athletes at the highest level is certainly interesting if you are in the small percentage of coaches who work in this group, but the concepts and ideas behind it can be helpful to understand, regardless of what population you end up working with. Daniel has come up with a unique system of load consolidation, working with an NBA population that makes a lot of sense.  Not only is “The Quadrant System” a wise method for pro athletes, but understanding the Quadrant System is also helpful from the perspective of understanding “high-low” style training in general (making high days truly “high” and low days, truly “low”), as well as the art of dealing with monotony over the course of long training periods.  On the show today, Daniel gets into his four quadrants of training (recovery, repetition, speed and of course, strength), and how he utilizes these methods of loading through different points in an in-season training schedule, as well as off-season. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 4:23 – How Daniel categorizes load for athletes that he works with 14:48 – How the quadrants might alter as athletes get further down away from the pro-level 15:58 – How high-low training and undulation of the type of stimulus players get offers substantial benefits for players, particularly those in the course of long playing seasons 20:22 – Daniel’s take on the “speed day” in the quadrant system, and how that balances with the explosive work and speed players are doing in their practice 25:48 – How the quadrant system may change when the strength coach doesn’t have a “seat at the table” of the sport coaches and practice volumes 32:05 – Validating heavy lifting in season, on the terms of what Daniel is seeing from data and force plates, and what types of volumes athletes are doing for heavy strength work in season 37:05 – How to approach heavy lifting after game-day if players had a poor game 40:24 – Daniel’s experience with buy-in and the spectrum of players responses in regards to heavy lifting on game-days 43:01 – Nuances of the heavy strength day and how Daniel chooses to load athletes on that day 44:45 – How Daniel approaches tendon health and the repetition day/quadrant 2 47:58 – How the quadrant system changes when athletes are in the off-season or in developmental cases in-season 50:14 – Daniel’s view on a daily micro-dosing program, versus a high-low, quadrant system oriented program, and common movements that may actually be micro-dosed in the pro/NBA setting 55:04 – How Daniel uses work that creates more movement potential within the hips, as a preparation for players to use that range of motion effectively on t...

Today’s show is with coach Brady Volmering.  Brady is the owner of DAC Performance and Health. After starting out in the world of baseball skill training, he’s since moved into the human performance arena, putting the focus on increasing the capacity of the human being.  Brady looks at what “training the human being” actually means and how that relates to increases in specific sports performance. Ever since I’ve been in a formal weight room training setting for athletes, I’ve really wondered about the thought process of how the various barbell and dumbbell exercises were going to help athletes actually be better at what they do on the field.  I’ve always tried to keep a close eye on elements of gym training that could possibly link to athletes who were more successful in their actual sport. It’s important to ask the question: “what is training?”, and realize that the answer includes “how” just as much as “what”.  Weights are just one tool, or manifestation of the ability to be strong, and if we zoom out from the tool of barbells and dumbbells, we can look at the process of training and adaptation on a broader level.  Muscle tension (and relaxation) can be achieved in a wide variety of ways.  If we take a close look at the mental, emotional, and physical components can be put into the simplest of exercises, we can make then a better conduit by which to improve the whole state of the athlete’s system. On today’s podcast, Brady gives us his experiences with training athletes on a “human” level.  He goes into the tool of isometric holds, and how to modulate those to draw out different intentions, into ideas on learning the way a child does, the importance of menu systems, as well as “breaking the rules” with higher repetition training schemes (and the qualities it takes to adapt to “unreasonable” training loads).  This is an “outside the box” episode that covers a lot of important concepts in training the total human for sport and beyond. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 4:51 – How Brady started in the specific skill training of baseball players, and how he transitioned into more “human level” training and performance 9:09 – How Brady views the transfer of training ideology in light of the “human layer”, or GPP layer of performance 15:35 – Different intentions Brady prescribes during exercises, particularly isometric type exercises 22:31 – Elements Brady notices that transfer between human-level skills and how an athlete is performing in their sport 29:22 – The mentality by which children make rapid progress in skills, and how to harness that developmental ideal 39:16 – How Brady looks at menu systems for athletes, and giving them the power of choice 47:49 – Brady’s take on “breaking the rules” with high volume training experiences 58:36 – Thoughts on the balance and handing of high volume training versus the minimal effective dose of work 1:02:32 – “Human level” principles of athletes who can absorb and adapt to training volume on a higher level 1:07:58 – What an average training session looks like for Brady in light of the principles discussed in the show 1:11:50 – How to look at sets and reps, versus the construct of time, to direct intention of the athlete 1:14:07 – Some single-joint, high rep modalities that Brady enjoys using at the end of training sessions “When I’m training a human, I’m not thinking at all about transfer to their sport” “The goal is the deep pushup is for them to direct their intent into whatever it is they are doing; the pushup is just one way to practice that” “That’s where the human aspect of things is “how can we go into the hum...

Adarian Barr, a seasoned coach and inventor known for his unique insights into human movement, dives into the world of rotational forces and their vital role in athletic performance. He emphasizes the importance of 'tumbling' actions for speed enhancement, challenging traditional linear movement perspectives. The discussion covers the mechanics of levers, optimal training methods, and the interconnections of upper and lower body performance. Adarian highlights how understanding biomechanics can revolutionize coaching techniques and improve overall athletic capabilities.

Today’s show is with Angus Bradley.  Angus is a strength coach and podcast host from Sydney, Australia.  He coaches out of Sydney CBD, co-hosts the Hyperformance podcast with his brother, Oscar, and is also an avid surfer.  Angus appeared previously on episode 249 of the podcast, talking about compressive strategies in weightlifting, as well as the impacts of those compressive effects on narrow infra-sternal angle individuals in particular. Angus is one of the most brilliant, and practical individuals I know in the world of strength training biomechanics, and connecting it to movement and practical outcomes.  When it comes to making sense of how our body structure and pressure systems fit with different setups in the weight room, and how this might apply to dynamic movement, Angus is a top individual to learn from. So often in the weight room, we will say that it is all “general” (which technically it is) but then use that as an excuse not to understand the movements we are utilizing in detail that fit with greater concepts of the gait cycle.  Connecting strength work to the gait cycle is key in better strength training practices, as well as individualization. On the show today, Angus covers the dimensions of exercises based on center of mass position relative to the foot, and how this connects with the gait cycle, as well as how much an athlete is being “pushed forward” (and why that is important).  He’ll cover delayed knee extension in both lifting and sprinting (and how they might connect), concepts of foot shapes, and gait, as well as his take on “floating heel” work not potentially being everything it’s cracked up to be.  Angus will also give some practical ideas on giving more sensory information to athletes unable to access early stance well, how far to take wide and narrow ISA types in terms of “balancing their weaknesses”, and much more. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 4:25 – How doing the “wrong” intervention in training can still lead to positive results 11:30 – Understanding the implications of working through the various positions of the center of mass in relation to the position of the feet, and what this means for degrees of freedom in movement 18:30 – Some performance implications of wide-vs. narrow ISA’s in regards to mid and late stance, and jump technique 23:15 – The idea of “hamstring curling” one’s self out of the hole of a squat in order to delay knee extension 28:45 – Where Angus sees the benefit in “floating heel” training, and where he finds it not very beneficial 34:45 – How to re-train athletes to “let their femurs be” in squatting when they’ve been taught to shove their knees out in the past 39:30 – Thoughts on oscillatory squatting (and split squatting) and its impact on the mid-stance phase of lifting 43:30 – A discussion on developing mid-stance, narrow ISA’s and single leg squatting 49:00 – Flat vs. high arched individuals and what this means for how this impacts athletes in early vs. late propulsion 56:50 – How Angus’s lockdown sprint work went, and lessons he learned with squatted running 1:02:00 – Thoughts on the role of the adductors in movement, why some people may feel them more (or less) in sprinting, and how to train them in the gym “You can grab (IR and ER) if you just start pulling athletes back… heavy lifting just has a tendency to shove people forward” “A sign of a good athlete to me, is they will respond to their environment” “You can simplify it by looking at where they are in the sagittal plane and looking at that map of the foot, looking at where they are in relation to that base of support… if the center of...

Today’s show is a Q&A with Joel Smith.  It’s a lot of fun to see the questions you all have, and putting together a list of answers. Some major themes in this show included the dynamics of how an athlete learns and acquires a skill, how to give athletes ideal constraints to learn a skill better (particularly on the level of the arms in sprinting and step-action in jumping), and then questions on training the spectrum of the force velocity curve. There also were a lot of questions and answers that lent to training individualization based on the individual structure of the body and if one is a “power or speed” based athlete, which relates to an athlete’s ribcage structure and ISA bias, and of course, a lot of speed oriented questions. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 1:15 – The difference in training fascial vs. elastic athletes 7:33 – How to train a “power” sprinter with poor top end speed 13:40 – Thoughts on training at different points on the force-velocity curve 24:06 – Arm action in sprinting, and constraint-driven coaching versus “positional” coaching 34:14 – Structuring a weight training and performance program for speed and acceleration 36:32 – Why some athletes have a long vs. short penultimate step in jumping 40:45 – Thoughts on in-season programming for team sports 46:56 – Dealing with a toe-sprain and learning to feel other parts of the foot 48:30 – Frequency of training with bodyweight iso holds 49:37 – Thoughts on “inside edge” vs. “outside edge” in movement and training 54:35 – Fascial awareness in movement 55:42 – Is concentric power building in the weightroom worthwhile? 57:01 – How to use falling/slipping/stumbling reflexes to our advantage in training About Joel Smith Joel Smith is the founder of Just Fly Sports and is a sports performance coach in Cincinnati, Ohio.  Joel hosts the Just Fly Performance Podcast, has authored several books on athletic performance, and trains numerous clients in the in-person and online space.  Joel was formerly a strength coach for 8 years at UC Berkeley, working with the Swim teams and post-graduate professional swimmers, as well as tennis, water polo, and track and field.  A track coach of 11 years, Joel coached for the Diablo Valley Track and Field Club for 7 years, and also has 6 years of experience coaching sprints, jumps, hurdles, pole vault and multi-events on the collegiate level, working at Wilmington College, and the University of Wisconsin, LaCrosse. Joel has coached 2 national champions, multiple All-Americans and school record holders in his time as a track coach. In the realm of strength and conditioning, his programs have assisted 5 athletes to Olympic berths that produced 9 medals and a world record performance at Rio in 2016. In 2011, Joel began Just Fly Sports with Jake Clark as a central platform to promote information for athletes and coaches to reach their highest potential.  In 2016 the first episode of the “Just Fly Performance Podcast” was released, now a leading source of education in the sports performance field.  The evolving mission of Just Fly Sports is focused on teaching athletes to realize their true, innate power, and achieve the highest joy in their training, competition, and in the community.

Today’s show welcomes back running coach and biomechanist, Helen Hall.  Helen is the author of “Even With Your Shoes On”.  She is an endurance athlete, minimalist ultra-distance runner, 6 times Ironman and credited with being the world’s first ‘barefoot’ Iron(wo)man.  Helen is the owner of the Perpetual Forward Motion School of Efficient Running, as well as a running injury clinic, using the latest movement science and gait analysis technology to help people find solutions for their pain and injuries.  She appeared on episode 180 speaking on all things joint mechanics and technique in running. One of the most common things I hear (and have seen, especially in my club track years) about athletes is those who have a heavy heel strike when they run.  Excessive passive forces in athletic motion is never a good thing, but it’s always important to understand binary concepts (you had a heel-strike or you didn’t) in further detail.  There is a spectrum of potential foot strike positions in running, and nobody stays on their heel in gait, as we always move towards the forefoot. On the show today, Helen goes in depth on heel striking and the biomechanics of the heel in the running cycle, as well as the difference in heel striking motions in jogging versus sprinting.  One of the topics I frequently enjoy covering is how the human body can interact with nature and natural features to optimize itself (which includes optimizing running technique) and Helen speaks on how one can use uphill and downhill grades to help athletes and individuals self-organize their own optimal running technique. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 5:27 – Why Helen feels individuals heel strike in the first place 11:33 – Helen’s “happy medium” when it comes to socks in running 14:28 – Helen’s view on the heel bone and pronation in the initial strike in running 21:03 – How Helen would help an athlete who heel strikes in a sprint when it is not desired 29:28 – The importance of relaxation and “letting” the body move and react, versus trying to force the body into motion 38:41 – Nuances of using uphill and downhill running, what to notice, and how to integrate that into one’s stride 45:29 – How un-even surfaces can create grounds by which individuals can self-organize their stride and foot action 48:35 – How to leverage hills to optimize the function of the glutes in running “I never change somebody’s first point of contact; their bodies change their first point of contact themselves” “There can’t be a right or wrong, since there are so many people whose first point of contact is the heel, and they are not in pain” “If you land in front of the heel, then you get the eccentric loading of the Achilles and what it attaches to” “People decide they are in “this camp” or “that camp” and thereby the camps run parallel to each other and never exchange ideas” “You want to be landing, not in a pronating foot.. in the context of running… the descent is arguably a posteriorly tilted calcaneus because you are landing in a supinating foot… unless your foot is going to go “splat” immediately” “You want to land on a foot that is relaxed enough to give” “They are reaching for the step, and by reaching on the step through hip flexion, they are ending up on their heel first, and that may be giving them more control as they go through the forefoot” “In my experience, people do not go back to the heel-strike, and all you need is a slope (to correct it)” “If you want to slow down, the most natural thing in the world is to shove your foot out, and brake with your heel” “You have to be relaxed for the response in you...

Today’s show welcomes back JB Morin.  JB Morin is currently full professor and head of sports science and the physical education department at the University of Saint-Etienne.  He has been involved in sport science research for over 15 years, and has published over 50 peer-reviewed journals since 2004.  JB is a world-leading researcher on all things sprint related, having collaborated with and analyzed some of the world’s best sprinters, such as Christophe Lemaitre. JB also does lots of sprint research that is highly applicable to team sport settings, such as information that can be gleaned from force-velocity profiling.  He has been a 2x previous guest on this podcast, speaking on elements of heavy sled training, force-velocity profiling, and much more. When it comes to sprinting from point A to point B, the time on the clock does not necessarily represent the strategy an athlete used to get there.  Athletes who can direct their sprint forces in more of a horizontal vector are going to be able to reach higher top velocities, and be more resilient towards injury. The question then becomes, how do we assess, and train athletes in respect to the direction they are producing sprint forces?  In today’s episode, JB speaks on how the specifics of an athlete’s force production (in the horizontal vs. vertical direction) will highlight elements of how fatigued that individual is, and their predisposition to injury in the short term.  JB also goes into how to measure force production in sprinting, new research on joint actions in early and late acceleration, hill training vs. sleds, hamstring research, and more. Today’s episode is brought to you by SimpliFaster, Inside Tracker, and Lost Empire Herbs. For 25% off of an Inside Tracker order go to info.insidetracker.com/justflysports For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. View more podcast episodes at the podcast homepage. Timestamps and Main Points 5:00 –  Some new work that has come out in sprint research recently, showing the importance of the hip and ankle outputs in sprinting, even in the first few steps of acceleration 16:20 –  Thoughts on sprint technique, or force-velocity profiling and how that might link to potential injury in team sport situations 24:00 –  The relationship (and differences) between one’s maximal horizontal force, and their maximal sprint speed, and what it means for injury risk 30:50 –  How having a poor maximal horizontal force output can show up in the biomechanics of how an athlete is sprinting 37:15 –  How elite athletes will start to change their force-production orientation (less horizontal, over time) once fatigue starts to set in during a training session 45:00 –  How hill training compares to heavy sled training in terms of forces and velocity 50:30 –  New studies and thoughts on hamstring injury in athletics 54:20 –  Thoughts on training the feet and lower leg for the sake of sprinting 58:40 –  JB’s thoughts on how to set up good research on sprinting in athletics “75% of the energy that is generated to run is generated at the hip and calf level” “Team sport is so chaotic, it’s the worst way to assess an athlete’s acceleration capability, the game environment is not reproducible” “Our studies show that pre-season maximal force output is not related to (injury risk) but when you measure that maximal force output throughout the season, the last measurement is related to the risk of injury in that measurement period” “You need to measure (force/velocity) regularly, not only in the pre-season period… there are so many changes throughout the season” “You can have people with the same 25 meter splits, but different profiles at the beginning of the spectrum or the end of the spectrum” “If you take two athletes with the same magnitude of ground reaction force, the best in acceleration will be the most horizontally oriented vector”