Three Problems, Six Experts and the Science of Advice
What to do when physical therapists, psychologists, and golf Instructors disagree
Three problems have affected me over the past few months. First, I've developed sciatic pain that runs from my hip to my foot; second, my golf slice has reappeared ruining my game; and third, my daughter has a two-year-old who is comparing and contrasting parenting advice from her parents, books, and the internet.
These seemingly disparate issues share a common thread: the challenge of navigating conflicting expert advice. As I sought solutions, I discovered a crucial factor distinguishing helpful guidance from potentially misguided recommendations: the degree to which the advice is grounded in scientific research.
The Sciatic Struggle
My search for relief from sciatic pain led me to two physical therapists with markedly different approaches. The first, adhering to the McKenzie Method, prescribed a series of extension-based exercises. This method, developed by Robin McKenzie in the 1960s, has been a mainstay in physical therapy for decades.
It wasn’t that helpful for me so I delved into recent research. I found that its scientific backing was less robust than I had assumed. A 2018 systematic review in the Journal of Orthopaedic & Sports Physical Therapy revealed only moderate evidence supporting the McKenzie Method for acute low back pain and limited evidence for its effectiveness in treating sciatica specifically.
A second therapist introduced me to the work of Dr. Stuart McGill, a spine biomechanist whose approach is firmly rooted in laboratory research. McGill's "Big 3" exercises - the curl-up, side bridge, and bird dog - are designed based on extensive studies of spine mechanics published in peer-reviewed journals like The Spine Journal. These exercises aim to enhance spine stability with minimal motion and low compressive load, a principle McGill's research indicates is crucial for back health. I’m following this strategy. I’m improving but at this early stage, I still have pain.
Bob Schrupp and Brad Heineck, known popularly as "Bob and Brad," are physical therapists who run a widely followed YouTube channel. They often recommend stretching exercises for various conditions, including sciatica. If you look on YouTube you will find videos such as, “8 stretches for sciatic pain relief”.
On the other hand, Dr. Stuart McGill, a spine biomechanist and former professor at the University of Waterloo, generally advises against stretching for back pain and sciatica, focusing instead on spine stabilization exercises. The sciatic nerve does not like to be stretched, he says. It will cause more pain.
So, do I stretch or no?
Here is what I discovered about research on stretching for sciatica:
A 2021 systematic review and meta-analysis published in the Journal of Orthopaedic & Sports Physical Therapy found that exercise therapy, including a combination of stretching and strengthening exercises, was effective in reducing pain and disability in people with sciatica. However, the authors noted that the quality of evidence was low to moderate.
A 2020 review in the European Spine Journal concluded that there is limited evidence to support the use of stretching alone for sciatica. The authors suggested that a combination of strengthening exercises, aerobic conditioning, and education may be more effective.
A 2019 study in the Archives of Physical Medicine and Rehabilitation found that a treatment approach including both McKenzie exercises (which involve some stretching) and neural mobilization techniques was more effective than either approach alone for sciatica.
McGill's own research, published in various journals including The Spine Journal, emphasizes the importance of spine stability and argues that certain stretches can exacerbate disc herniation, potentially worsening sciatica symptoms.
The current consensus in the scientific literature seems to be that while stretching alone may not be the most effective treatment for sciatica, a comprehensive approach that includes some stretching, strengthening exercises, stability work, and other interventions (like education and aerobic conditioning) can be beneficial. However, the type and extent of stretching should be considered based on the individual's specific condition.
It's worth noting that the conflicting advice between Bob & Brad and Stuart McGill reflects the ongoing debate in the field and the complexity of treating back pain and sciatica.
Slice and Science
My resurgent golf slice led me down a similar path of conflicting advice. One golf pro, following traditional teachings, focused on adjusting my grip and swing path based on observational experience. Another introduced me to modern swing analysis technology, using launch monitors and 3D motion capture to diagnose my swing faults.
One instructor I used some years ago placed a thin fiberglass rod vertically about 12 inches past my right foot. My task was to move my 7 iron over, past, and around the rod then hit the ball using an inside outward swing. My faulty swing is outside in instead of inside out. On the other hand, my current instructor told me to take the club away from the ball and follow a thin rod on the ground. At the top of the backswing, he physically prompted me to bring the club down and hopefully square the face of the iron as I hit the ball and followed through. I practiced until I could do it without the physical prompt. He used launch monitors and videos to provide feedback. I haven’t completed my lessons or practiced enough so my slice isn’t quite cured, yet.
Here are four research-based tips for eliminating a slice, which often contradict traditional advice:
Focus on Club Face, Not Swing Path
Conventional wisdom: Many instructors focus primarily on correcting an out-to-in swing path to fix a slice.
Research-based tip: Studies, including those by Dr. Mark Broadie, have shown that club face angle at impact has a much greater influence on ball flight than swing path. In fact, face angle accounts for about 85% of a ball's initial direction.
Use a Stronger Grip, But Not Too Strong
Conventional wisdom: A common quick fix for a slice is to strengthen the grip significantly.
Research-based tip: Research by Dr. Paul Wood and others has shown that while a stronger grip can help, an overly strong grip can lead to other issues. The optimal grip strength varies by individual.
Increase Spin Loft for More Consistent Shots
Conventional wisdom: Many golfers try to "hit down" on the ball to reduce slicing.
Research-based tip: TrackMan data analyzed by Dr. Sasho MacKenzie has shown that a slightly increased angle of attack (hitting more up on the ball) can actually lead to more consistent shots and potentially reduce slice spin.
Use Variable Practice to Improve Face Control
Conventional wisdom: Traditional anti-slice practice often involves hitting the same shot repeatedly.
Research-based tip: Motor learning research, including studies in golf, shows that variable practice leads to better skill acquisition and transfer. Practice intentionally hitting slices, draws, and straight shots. This variability helps develop better control over the club face.
Last, it's crucial to maintain a balance between technical practice and playing the game. Research shows that too much focus on technique can lead to paralysis by analysis. Spend time playing golf, not just practicing on the range, to develop a more holistic golf skill set.
Parenting in the Age of Information
My daughter's quest for effective parenting strategies for her two-year-old mirrors my own searches for health and golf advice. She's encountered a spectrum of recommendations, from strictly behavioral approaches to more emotion-focused strategies.
Dr. Alan Kazdin's methods, developed at the Yale Parenting Center, stand out for their strong grounding in behavioral science. Kazdin's approach, emphasizing positive reinforcement and strategic attention management, has been validated through numerous peer-reviewed studies. A 2016 study in the Journal of Child and Family Studies demonstrated the effectiveness of his techniques in reducing disruptive child behaviors.
In contrast, approaches like Dr. Laura Markham's "peaceful parenting" and Dr. Dan Siegel's "whole-brain" parenting, while popular and potentially insightful, rely more heavily on attachment theory and neuroscience concepts that haven't been subjected to the same rigorous, controlled studies as Kazdin's methods. While these approaches may offer valuable perspectives on parent-child relationships, their specific recommendations lack an adequate level of empirical support.
The Science of Advice
Through these experiences - with back pain, golf, and parenting advice - a clear pattern emerges. While advice based on personal experience or theoretical models can be compelling and sometimes helpful, guidance grounded in rigorous scientific research tends to be more reliable and effective.
It's helpful to distinguish between different types of research as well. Correlational studies, while predictive, don't provide the same level of evidence as experimental research, particularly randomized controlled trials or well-designed single-subject studies. These more rigorous methodologies allow for stronger causal inferences about the effectiveness of specific techniques or interventions.
As consumers of expert advice, we must use our scientific literacy to navigate a sea of conflicting opinions. In an age where information is abundant but unreliable, the ability to discern scientifically grounded advice from mere opinion is invaluable. Whether we're seeking relief from physical pain, improving our golf game, or raising well-adjusted children, our best path forward is one illuminated by the light of scientific evidence.